Compounds useful for treating disorders related to TRPA1

ABSTRACT

Compounds and compositions for treating disorders related to TRPA1 are described herein.

PRIORITY CLAIM

This application claims priority to U.S. Ser. No. 61/148,296, filed Jan.29, 2009, which is hereby incorporated by reference in its entirety.

BACKGROUND

The invention relates to compounds and compositions useful for treatingdisorders related to TRPA1.

A variety of ion channel proteins exist to mediate ion flux acrosscellular membranes. The proper expression and function of ion channelproteins is essential for the maintenance of cell function andintracellular communication. Numerous diseases are the result ofmisregulation of membrane potential or aberrant calcium handling. Giventhe central importance of ion channels in modulating membrane potentialand ion flux in cells, identification of agents that can promote orinhibit particular ion channels are of great interest, both as researchtools and as therapeutic agents.

SUMMARY OF THE INVENTION

The invention provides compounds, methods and compositions for treatingor preventing conditions such as pain by modulating the activity of theTRPA1 channel. The compounds described herein can modulate the functionof TRPA1 by inhibiting a TRPA1-mediated ion flux or by inhibiting theinward current, the outward current, or both currents mediated by TRPA1.The inhibition of a particular current is the ability to inhibit orreduce such current (e.g., inward and/or outward) in an in vitro or anin vivo assay. (See Jordt et al. (2004), Nature 427:260-265; Bautista etal., (2005) PNAS: 102(34):12248-12252).

In one aspect, the invention features a method of treating a TRPA1mediated disorder in a subject. The method includes administering aneffective amount of a compound of formula I, or a pharmaceuticallyacceptable salt thereof:

Each of A, B, C, and D is CR¹ or N, provided that no more than 2 of A,B, C, and D are N; in addition, each of X and Y is, independently, N—R,O or S, where R is H, optionally substituted C₁₋₆ alkyl, OH, OR′, CN,NO₂, or SO₂R′, where R′ is H or C₁₋₆ alkyl; each R¹ is, independently,H, optionally substituted C₁₋₆ alkyl, optionally substituted C₂₋₆alkenyl, optionally substituted C₂₋₆ alkynyl, optionally substitutedheterocyclyl, hydroxyl, optionally substituted C₁₋₆ alkoxy, optionallysubstituted C₁₋₆ alkenyloxy, cyano, halo, acyl, amino, optionallysubstituted alkylamino, aminoalkyl, amido, acylamino, alkylurea,alkylcarbamoyl, carboxyl, optionally substituted alkylcarboxyl, thioyl,optionally substituted alkylthio, SO₃H, alkylsulfinyl, optionallysubstituted alkylsulfonyl, or nitro. R² is optionally substitutedcycloalkyl, optionally substituted heterocyclyl, optionally substitutedaryl or optionally substituted heteroaryl; each of R³ and R⁴ is,independently, H, optionally substituted C₁₋₆ alkyl, arylalkyl,heteroarylalkyl, alkoxyalkyl, COR¹⁰, CO₂R¹⁰, CH₂CO₂R¹⁰, or CONHR¹⁰,where R¹⁰ is H or optionally substituted C₁₋₆ alkyl. In someembodiments, at least one of A, B, C, or D is N. For example, in someembodiments, D is N.

In another aspect, the invention features a method of treating pain in asubject. The method includes administering an effective amount of acompound of formula I, or a pharmaceutically acceptable salt thereof:

where the substituents are defined as above. In some embodiments, atleast one of A, B, C, or D is N. For example, in some embodiments, D isN.

In another aspect, the invention features a compound having Formula III,or a pharmaceutically acceptable salt thereof:

where each of A, B, C, and D is CR¹ or N, provided that no more than 2of A, B, C, and D are N. In addition, each R¹ is, independently, H,optionally substituted C₁₋₆ alkyl, optionally substituted C₂₋₆ alkenyl,optionally substituted C₂₋₆ alkynyl, optionally substitutedheterocyclyl, hydroxyl, optionally substituted C₁₋₆ alkoxy, C₁₋₆alkenyloxy, cyano, halo, acyl, amino, optionally substituted alkylamino,aminoalkyl, amido, acylamino, alkylurea, alkylcarbamoyl, carboxyl,optionally substituted alkylcarboxyl, thioyl, optionally substitutedalkylthio, SO₃H, optionally substituted alkylsulfinyl, optionallysubstituted alkylsulfonyl, or nitro; R² is optionally substitutedcycloalkyl, optionally substituted heterocyclyl, optionally substitutedaryl or optionally substituted heteroaryl; and each of R³ and R⁴ is,independently, H, optionally substituted C₁₋₆ alkyl, arylalkyl,heteroarylalkyl, alkoxyalkyl, COR¹⁰, CO₂R¹⁰, CH₂CO₂R¹⁰, or CONHR¹⁰,where R¹⁰ is H or optionally substituted C₁₋₆ alkyl. However, when A, B,C, and D are all CH, and R³ and R⁴ are both H, then R² cannot be3-nitrophenyl, naphthyl, 2-halophenyl, 3,4,5-trimethoxyphenyl,2,3-dihydroxyphenyl, unsubstituted phenyl, pyridyl, 4-alkylphenyl,4-alkoxyphenyl, 4-hydroxyphenyl, 4-halophenyl, 4-nitrophenyl,benzo-11,31-dioxole. In addition, when A, B, C, and D are all CH and R²is unsubstituted phenyl or 3,4,5-trimethoxyphenyl, then neither of R³and R⁴ can be methyl.

In some embodiments, at least one of A, B, C, or D is N. For example, insome embodiments, D is N. In some embodiments, R² is optionallysubstituted phenyl, e.g., meta-substituted phenyl.

In another aspect, the invention features a compound of Formula V, or apharmaceutically acceptable salt thereof:

where each of A, B, C, and D is CR¹ or N, provided that no more than 2of A, B, C, and D are N;each of X and Y is, independently, N—R, O or S, where R is H, alkyl, OH,OR′, CN, NO₂, or SO₂R′, where R′ is H or C₁₋₆ alkyl; each R¹ is,independently, H, optionally substituted C₁₋₆ alkyl, optionallysubstituted C₂₋₆ alkenyl, optionally substituted C₂₋₆ alkynyl,optionally substituted heterocyclyl, hydroxyl, optionally substitutedC₁₋₆ alkoxy, optionally substituted C₁₋₆ alkenyloxy, cyano, halo, acyl,amino, optionally substituted alkylamino, aminoalkyl, amido, acylamino,alkylurea, alkylcarbamoyl, carboxyl, optionally substitutedalkylcarboxyl, thioyl, optionally substituted alkylthio, SO₃H,optionally substituted alkylsulfinyl, optionally substitutedalkylsulfonyl, or nitro; each of R³ and R⁴ is, independently, H,optionally substituted C₁₋₆ alkyl, arylalkyl, heteroarylalkyl,alkoxyalkyl, COR¹⁰, CO₂R¹⁰, CH₂CO₂R¹⁰, or CONHR¹⁰, where R¹⁰ is H oroptionally substituted C₁₋₆ alkyl; R⁵ is hydroxyl, optionallysubstituted C₁₋₆ alkoxy, optionally substituted C₁₋₆ alkenyloxy,alkyloxyalkoxy, cyano, acyl, amino, optionally substituted alkylamino,aminoalkyl, amido, acylamino, alkylurea, alkylcarbamoyl, carboxyl,optionally substituted alkylcarboxyl, thioyl, optionally substitutedalkylthio, SO₃H, optionally substituted alkylsulfinyl, or optionallysubstituted alkylsulfonyl. In some embodiments, at least one of A, B, C,or D is N. For example, in some embodiments, D is N.

In another aspect, the invention features a compound having Formula VII,or a pharmaceutically acceptable salt thereof:

where each of A, B, C, and D is CR¹ or N, provided that no more than 1of A, B, C, and D is N;each of X and Y is, independently, N—R, O or S, where R is H, alkyl, OH,OR′, CN, NO₂, or SO₂R′, where R′ is H or C₁₋₆ alkyl; each R¹ is,independently, H, optionally substituted C₁₋₆ alkyl, optionallysubstituted C₂₋₆ alkenyl, optionally substituted C₂₋₆ alkynyl,optionally substituted heterocyclyl, hydroxyl, optionally substitutedC₁₋₆ alkoxy, optionally substituted C₁₋₆ alkenyloxy, cyano, halo, acyl,amino, optionally substituted alkylamino, aminoalkyl, amido, acylamino,alkylurea, alkylcarbamoyl, carboxyl, optionally substitutedalkylcarboxyl, thioyl, optionally substituted alkylthio, SO₃H,optionally substituted alkylsulfinyl, optionally substitutedalkylsulfonyl, or nitro; each of R³ and R⁴ is, independently, H,optionally substituted C₁₋₆ alkyl, arylalkyl, heteroarylalkyl,alkoxyalkyl, COR¹⁰, CO₂R¹⁰, CH₂CO₂R¹⁰, or CONHR¹⁰, where R¹⁰ is H oroptionally substituted C₁₋₆ alkyl; R⁶ is hydroxyl, C₁₋₆ alkenyloxy,cyano, acyl, amino, optionally substituted alkylamino, aminoalkyl,amido, acylamino, alkylurea, alkylcarbamoyl, carboxyl, optionallysubstituted alkylcarboxyl, thioyl, optionally substituted alkylthio,SO₃H, optionally substituted alkylsulfinyl, or optionally substitutedalkylsulfonyl. In some embodiments, at least one of A, B, C, or D is N.For example, in some embodiments, D is N.

In another aspect, the invention features a compound having FormulaVIII, or a pharmaceutically acceptable salt thereof:

wherein each of R1 and R² is, independently, H, optionally substitutedC₁₋₆ alkyl, arylalkyl, heteroarylalkyl, alkoxyalkyl, COR¹⁰, CO₂R¹⁰,CH₂R¹⁰, or CONHR¹⁰, where R¹⁰ is H or optionally substituted C₁₋₆ alkyl;and each R³ is, independently, hydroxyl, optionally substituted C₁₋₆alkoxy, optionally substituted C₁₋₆ alkenyloxy, alkyloxyalkoxy, cyano,acyl, amino, optionally substituted alkylamino, aminoalkyl, amido,acylamino, alkylurea, alkylcarbamoyl, carboxyl, optionally substitutedalkylcarboxyl, thioyl, optionally substituted alkylthio, SO₃H,optionally substituted alkylsulfinyl, or optionally substitutedalkylsulfonyl; and n is 1-3. In some embodiments, the compound hasFormula IX. In other embodiments, the compound has the formula IXa.

In another embodiment, the invention features a compound having FormulaX, or a pharmaceutically acceptable salt thereof:

wherein each of R¹ and R² is, independently, H, optionally substitutedC₁₋₆ alkyl, arylalkyl, heteroarylalkyl, alkoxyalkyl, COR¹⁰, CO₂R¹⁰,CH₂CO₂R¹⁰, or CONHR¹⁰, where R¹⁰ is H or optionally substituted C₁₋₆alkyl; each R³ is, independently, hydroxyl, optionally substituted C₁₋₆alkoxy, optionally substituted C₁₋₆ alkenyloxy, alkyloxyalkoxy, cyano,acyl, amino, optionally substituted alkylamino, aminoalkyl, amido,acylamino, alkylurea, alkylcarbamoyl, carboxyl, optionally substitutedalkylcarboxyl, thioyl, optionally substituted alkylthio, SO₃H,optionally substituted alkylsulfinyl, or optionally substitutedalkylsulfonyl; and n is 1-3. In some embodiments, the compound hasFormula XI. In other embodiments, the compound has Formula XIa.

Included within the scope of the invention are, for each compounddescribed herein, the salts thereof, or a solvate, hydrate, oxidativemetabolite or prodrug of the compound or its salt. When the compoundsare referred to herein, it is understood that salts, solvates, hydrates,oxidative metabolites, and prodrugs of the compounds are also included.Tautomers of the compounds disclosed are also included within the scopeof the invention.

Any of the compounds disclosed herein may be used to treat any diseasesdisclosed herein. In addition, these compounds may be used to inhibit afunction of a TRPA1 channel in vitro or in vivo.

DETAILED DESCRIPTION OF THE INVENTION Definitions

The term “acyl” refers to a group represented by the general formulahydrocarbylC(O)—, preferably alkylC(O)—.

The term “acylamino” refers to a moiety that can be represented by thegeneral formula:

wherein R₉ is as defined below, and R′¹¹ represents a hydrogen, analkyl, an alkenyl or —(CH₂)_(m)—R⁸, where m and R⁸ are as definedherein.

The term “aliphatic group” refers to a straight-chain, branched-chain,or cyclic aliphatic hydrocarbon group and includes saturated andunsaturated aliphatic groups, such as an alkyl group, an alkenyl group,and an alkynyl group.

The term “alkenyl,” as used herein, refers to an aliphatic groupcontaining at least one double bond.

The terms “alkoxyl” or “alkoxy” as used herein refers to an alkyl group,as defined below, having an oxygen radical attached thereto.Representative alkoxyl groups include methoxy, ethoxy, propyloxy,tert-butoxy and the like. An “ether” is two hydrocarbons covalentlylinked by an oxygen.

The term “alkyl” refers to the radical of saturated aliphatic groups,including straight-chain alkyl groups, branched-chain alkyl groups,cycloalkyl (alicyclic) groups, alkyl-substituted cycloalkyl groups, andcycloalkyl-substituted alkyl groups. In preferred embodiments, astraight chain or branched chain alkyl has 30 or fewer carbon atoms inits backbone (e.g., C1-C30 for straight chains, C3-C30 for branchedchains), and more preferably 20 or fewer, and most preferably 10 orfewer. Likewise, preferred cycloalkyls have from 3-10 carbon atoms intheir ring structure, and more preferably have 5, 6 or 7 carbons in thering structure.

The term “alkynyl”, as used herein, refers to an aliphatic groupcontaining at least one triple bond.

The term “alkylurea” refers to a group having the structure—NHC(═O)NH-alkyl.

The term “alkylcarbamoyl” refers to a group having the structure—NHCO₂-alkyl.

The term “alkylthio” refers to a hydrocarbyl group having a sulfurradical attached thereto. In some embodiments, the “alkylthio” moiety isrepresented by one of —S-alkyl, —S-alkenyl, or —S-alkynyl.Representative alkylthio groups include methylthio, ethylthio, and thelike.

The terms “amine” and “amino” refer to both unsubstituted andsubstituted amines, e.g., a moiety that can be represented by thegeneral formula:

wherein R₉, R₁₀ and R′₁₀ each independently represent a hydrogen, analkyl, an alkenyl, —(CH₂)_(m)—R₈, or R₉ and R₁₀ taken together with theN atom to which they are attached complete a heterocycle having from 4to 8 atoms in the ring structure; R₈ represents an aryl, a cycloalkyl, acycloalkenyl, an alkoxy, a heterocycle or a polycycle; and m is zero oran integer in the range of 1 to 8.

The term “amido” refers to a moiety that can be represented by thegeneral formula:

wherein R₉, R₁₀ are as defined above.

The term “aralkyl”, as used herein, refers to an alkyl group substitutedwith an aryl group (e.g., an aromatic or heteroaromatic group).

The term “aryl” as used herein includes 5-, 6-, and 7-memberedsingle-ring aromatic groups that may include from zero to fourheteroatoms, for example, benzene, pyrrole, furan, thiophene, imidazole,oxazole, thiazole, triazole, pyrazole, pyridine, pyrazine, pyridazineand pyrimidine, and the like. Those aryl groups having heteroatoms inthe ring structure may also be referred to as “aryl heterocycles” or“heteroaromatics.” The aromatic ring can be substituted at one or morering positions with such substituents as described above, for example,halogen, azide, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl,polycyclyl, hydroxyl, alkoxyl, amino, nitro, sulfhydryl, imino, amido,phosphate, phosphonate, phosphinate, carbonyl, carboxyl, silyl, ether,alkylthio, sulfonyl, sulfonamido, ketone, aldehyde, ester, heterocyclyl,aromatic or heteroaromatic moieties, —CF3, —CN, or the like. The term“aryl” also includes polycyclic ring systems having two or more cyclicrings in which two or more carbons are common to two adjoining rings(the rings are “fused rings”) wherein at least one of the rings isaromatic, e.g., the other cyclic rings can be cycloalkyls,cycloalkenyls, cycloalkynyls, aryls and/or heterocyclyls. Each ring cancontain, e.g., 5-7 members.

The term “carbocycle or cyclyl,” as used herein, refers to an aromaticor non-aromatic ring in which each atom of the ring is carbon.

The term “carbonyl” refers to moieties represented by the generalformula:

wherein X is a bond or represents an oxygen or a sulfur, and R₁₁represents a hydrogen, an alkyl, an alkenyl, —(CH₂)_(m)—R₈ or apharmaceutically acceptable counter-ion, R′₁₁ represents a hydrogen, analkyl, an alkenyl or —(CH₂)_(m)—R₈, where m and R₈ are as defined above.Where X is an oxygen and R₁₁ or R′₁₁ is not hydrogen, the formularepresents an “ester”. Where X is an oxygen, and R₁₁ is as definedabove, the moiety is referred to herein as a carboxyl group, andparticularly when R₁₁ is a hydrogen, the formula represents a“carboxylic acid”. Where X is an oxygen, and R′₁₁ is hydrogen, theformula represents a “formate”. In general, where the oxygen atom of theabove formula is replaced by sulfur, the formula represents a“thiocarbonyl” group. Where X is a sulfur and R₁₁ or R′₁₁ is nothydrogen, the formula represents a “thioester.” Where X is a sulfur andR₁₁ is hydrogen, the formula represents a “thiocarboxylic acid.” Where Xis a sulfur and R₁₁′ is hydrogen, the formula represents a“thioformate.” On the other hand, where X is a bond, and R₁₁ is nothydrogen, the above formula represents a “ketone” group. Where X is abond, and R₁₁ is hydrogen, the above formula represents an “aldehyde”group.

The term “ester”, as used herein, refers to a group —C(O)OR⁹ wherein R⁹represents a hydrocarbyl group.

The terms “halo” and “halogen” as used herein means halogen and includeschloro, fluoro, bromo, and iodo.

The terms “hetaralkyl” and “heteroaralkyl”, as used herein, refers to analkyl group substituted with a heteroaryl group.

The term “heteroaryl” refers to an aromatic 5-8 membered monocyclic,8-12 membered bicyclic, or 11-14 membered tricyclic ring system having1-3 heteroatoms if monocyclic, 1-6 heteroatoms if bicyclic, or 1-9heteroatoms if tricyclic, said heteroatoms selected from O, N, or S(e.g., carbon atoms and 1-3, 1-6, or 1-9 heteroatoms of N, O, or S ifmonocyclic, bicyclic, or tricyclic, respectively). Any ring atom can besubstituted (e.g., by one or more substituents).

The terms “heterocyclyl” or “heterocyclic group” refer to 3- to10-membered ring structures, more preferably 3- to 7-membered rings,whose ring structures include one to four heteroatoms. Heterocycles canalso be polycycles, with each group having, e.g., 5-7 ring members.Heterocyclyl groups include, for example, thiophene, thianthrene, furan,pyran, isobenzofuran, chromene, xanthene, phenoxathiin, pyrrole,imidazole, pyrazole, isothiazole, isoxazole, pyridine, pyrazine,pyrimidine, pyridazine, indolizine, isoindole, indole, indazole, purine,quinolizine, isoquinoline, quinoline, phthalazine, naphthyridine,quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline,phenanthridine, acridine, pyrimidine, phenanthroline, phenazine,phenarsazine, phenothiazine, furazan, phenoxazine, pyrrolidine, oxolane,thiolane, oxazole, piperidine, piperazine, morpholine, lactones, lactamssuch as azetidinones and pyrrolidinones, sultams, sultones, and thelike. The heterocyclic ring can be substituted at one or more positionswith such substituents as described above, as for example, halogen,alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, amino, nitro,sulfhydryl, imino, amido, phosphate, phosphonate, phosphinate, carbonyl,carboxyl, silyl, ether, alkylthio, sulfonyl, ketone, aldehyde, ester, aheterocyclyl, an aromatic or heteroaromatic moiety, —CF₃, —CN, or thelike.

The term “heterocyclylalkyl”, as used herein, refers to an alkyl groupsubstituted with a heterocycle group.

The term “hydrocarbyl”, as used herein, refers to a group that is bondedthrough a carbon atom that does not have a ═O or ═S substituent, andtypically has at least one carbon-hydrogen bond and a primarily carbonbackbone, but may optionally include heteroatoms. Thus, groups likemethyl, ethoxyethyl, 2-pyridyl, and trifluoromethyl are considered to behydrocarbyl for the purposes of this application, but substituents suchas acetyl (which has a ═O substituent on the linking carbon) and ethoxy(which is linked through oxygen, not carbon) are not. Hydrocarbyl groupsinclude, but are not limited to aryl, heteroaryl, carbocycle,heterocycle, alkyl, alkenyl, alkynyl, and combinations thereof.

As used herein, the term “nitro” means —NO2; the term “halogen” or“halo” designates —F, —Cl, —Br or —I; the term “sulfhydryl” means —SH;the term “hydroxyl” means —OH; and the term “sulfonyl” means —SO₂—.

The terms “polycyclyl” or “polycyclic group” refer to two or more rings(e.g., cycloalkyls, cycloalkenyls, cycloalkynyls, aryls and/orheterocyclyls) in which two or more carbons are common to two adjoiningrings, e.g., the rings are “fused rings”. Rings that are joined throughnon-adjacent atoms are termed “bridged” rings. Each of the rings of thepolycycle can be substituted with such substituents as described above,as for example, halogen, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl,hydroxyl, amino, nitro, sulfhydryl, imino, amido, phosphate,phosphonate, phosphinate, carbonyl, carboxyl, silyl, ether, alkylthio,sulfonyl, ketone, aldehyde, ester, a heterocyclyl, an aromatic orheteroaromatic moiety, —CF₃, —CN, or the like.

The phrase “protecting group” as used herein means temporarysubstituents which protect a potentially reactive functional group fromundesired chemical transformations. Examples of such protecting groupsinclude esters of carboxylic acids, silyl ethers of alcohols, andacetals and ketals of aldehydes and ketones, respectively. The field ofprotecting group chemistry has been reviewed (Greene, T. W.; Wuts, P. G.M. Protective Groups in Organic Synthesis, 2^(nd) ed.; Wiley: New York,1991).

The term “substituted” refers to moieties having substituents replacinga hydrogen on one or more carbons of the backbone. It will be understoodthat “substitution” or “substituted with” includes the implicit provisothat such substitution is in accordance with permitted valence of thesubstituted atom and the substituent, and that the substitution resultsin a stable compound, e.g., which does not spontaneously undergotransformation such as by rearrangement, cyclization, elimination, etc.As used herein, the term “substituted” is contemplated to include allpermissible substituents of organic compounds. In a broad aspect, thepermissible substituents include acyclic and cyclic, branched andunbranched, carbocyclic and heterocyclic, aromatic and non-aromaticsubstituents of organic compounds. The permissible substituents can beone or more and the same or different for appropriate organic compounds.For purposes of this invention, the heteroatoms such as nitrogen mayhave hydrogen substituents and/or any permissible substituents oforganic compounds described herein which satisfy the valences of theheteroatoms. Substituents can include any substituents described herein,for example, a halogen, a hydroxyl, a carbonyl (such as a carboxyl, analkoxycarbonyl, a formyl, or an acyl), a thiocarbonyl (such as athioester, a thioacetate, or a thioformate), an alkoxyl, a phosphoryl, aphosphate, a phosphonate, a phosphinate, an amino, an amido, an amidine,an imine, a cyano, a nitro, an azido, a sulfhydryl, an alkylthio, asulfate, a sulfonate, a sulfamoyl, a sulfonamido, a sulfonyl, aheterocyclyl, an aralkyl, or an aromatic or heteroaromatic moiety. Itwill be understood by those skilled in the art that the moietiessubstituted on the hydrocarbon chain can themselves be substituted, ifappropriate. For instance, the substituents of a substituted alkyl mayinclude substituted and unsubstituted forms of amino, azido, imino,amido, phosphoryl (including phosphonate and phosphinate), sulfonyl(including sulfate, sulfonamido, sulfamoyl and sulfonate), and silylgroups, as well as ethers, alkylthios, carbonyls (including ketones,aldehydes, carboxylates, and esters), —CF₃, —CN and the like. Exemplarysubstituted alkyls are described below. Cycloalkyls can be furthersubstituted with alkyls, alkenyls, alkoxys, alkylthios, aminoalkyls,carbonyl-substituted alkyls, —CF₃, —CN, and the like. Analogoussubstitutions can be made to alkenyl and alkynyl groups to produce, forexample, aminoalkenyls, aminoalkynyls, amidoalkenyls, amidoalkynyls,iminoalkenyls, iminoalkynyls, thioalkenyls, thioalkynyls,carbonyl-substituted alkenyls or alkynyls.

The term “sulfate” refers to a moiety that can be represented by thegeneral formula:

in which R41 is as defined herein.

The term “sulfonamido” refers to a moiety that can be represented by thegeneral formula:

in which R₉ and R′¹¹ are as defined above.

The term “sulfonate” refers to a moiety that can be represented by thegeneral formula:

in which R41 is an electron pair, hydrogen, alkyl, cycloalkyl, or aryl.

The terms “sulfoxido” or “sulfinyl,” as used herein, refers to a moietythat can be represented by the general formula —S(═O)—R44, in which R44is selected from the group consisting of hydrogen, alkyl, alkenyl,alkynyl, cycloalkyl, heterocyclyl, aralkyl, or aryl.

The term “thioester,” as used herein, refers to a group —C(O)SR⁹ or—SC(O)R⁹ wherein R⁹ represents a hydrocarbyl.

As used herein, the definition of each expression, e.g., alkyl, m, n,etc., when it occurs more than once in any structure, is intended to beindependent of its definition elsewhere in the same structure.

Exemplary monocyclic rings include furan, thiophene, pyrrole, pyrroline,pyrrolodine, oxazole, thiazole, imidazole, imidazoline, pyrazole,pyrazoline, pyrazolidine, isoxazole, isothiazole, oxadiazole, triazole,thiadiazole, pyran, pyridine, piperidine, dioxane, morpholine, dithiane,thiomorpholine, pyridazine, pyrimidine, pyrazine, piperazine, triazine,and trithiane.

Exemplary bicyclic rings include indolizinyl, indolyl, isoindolyl,indolinyl, benzofuranyl, benzothiophenyl, indazolyl, benzimidazolyl,benthiazolyl, purinyl, quinolizinyl, quinolinyl, isoquinolinyl,cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl,pteridinyl, indenyl, naphthalenyl, azulenyl, imidazopyridazionyl,pyrazolopyrimidinedionyl, or pyrrolopyrimidinedionyl moieties.

Exemplary tricyclic rings include carbazole, acridine, phenazine,phenothiazine, phenoxazine, fluorine, and anthracene.

Certain compounds disclosed herein may exist in particular geometric orstereoisomeric forms. The present invention contemplates all suchcompounds, including cis- and trans-isomers, R- and S-enantiomers,diastereomers, (d)-isomers, (l)-isomers, the racemic mixtures thereof,and other mixtures thereof, as falling within the scope of theinvention. For example, if one chiral center is present in a molecule,the invention includes racemic mixtures, enantiomerically enrichedmixtures, and substantially enantiomerically pure compounds. Thecomposition can contain, e.g., more than 50%, more than 60%, more than70%, more than 80%, more than 90%, more than 95%, or more than 99% of asingle enantiomer.

The “enantiomeric excess” or “% enantiomeric excess” of a compositioncan be calculated using the equation shown below. In the example shownbelow a composition contains 90% of one enantiomer, e.g., the Senantiomer, and 10% of the other enantiomer, i.e., the R enantiomer.ee=(90−10)/100=80%.Thus, a composition containing 90% of one enantiomer and 10% of theother enantiomer is said to have an enantiomeric excess of 80%.

Methods of preparing substantially isomerically pure compounds are knownin the art. If, for instance, a particular enantiomer of a compounddisclosed herein is desired, it may be prepared by asymmetric synthesis,or by derivation with a chiral auxiliary, where the resultingdiastereomeric mixture is separated and the auxiliary group cleaved toprovide the pure desired enantiomers. Alternatively, where the moleculecontains a basic functional group, such as amino, or an acidicfunctional group, such as carboxyl, diastereomeric salts may be formedwith an appropriate optically active acid or base, followed byresolution of the diastereomers thus formed by fractionalcrystallization or chromatographic means well known in the art, andsubsequent recovery of the pure enantiomers. Alternatively,enantiomerically enriched mixtures and pure enantiomeric compounds canbe prepared by using synthetic intermediates that are enantiomericallypure in combination with reactions that either leave the stereochemistryat a chiral center unchanged or result in its complete inversion.Techniques for inverting or leaving unchanged a particular stereocenter,and those for resolving mixtures of stereoisomers are well known in theart, and it is well within the ability of one of skill in the art tochoose an appropriate method for a particular situation. See, generally,Furniss et al. (eds.), Vogel's Encyclopedia of Practical OrganicChemistry 5^(th) Ed., Longman Scientific and Technical Ltd., Essex,1991, pp. 809-816; and Heller, Acc. Chem. Res. 23: 128 (1990).

Contemplated equivalents of the compounds described above includecompounds which otherwise correspond thereto, and which have the samegeneral properties thereof (e.g., the ability to inhibit TRPA1activity), wherein one or more simple variations of substituents aremade which do not adversely affect the efficacy of the compound. Ingeneral, the compounds disclosed herein may be prepared by the methodsillustrated in the general reaction schemes as, for example, describedbelow, or by modifications thereof, using readily available startingmaterials, reagents and conventional synthesis procedures. In thesereactions, it is also possible to make use of variants which are inthemselves known, but are not mentioned here.

The compounds described herein may also contain unnatural proportions ofatomic isotopes at one or more of the atoms that constitute suchcompounds. For example, the compounds may be radiolabeled withradioactive isotopes, such as for example tritium (³H), iodine-125(¹²⁵I) or carbon-14 (¹⁴C). All isotopic variations of the compoundsdisclosed herein, whether radioactive or not, are intended to beencompassed within the scope of the present invention. For example,deuterated compounds and compounds incorporating ¹³C are intended to beencompassed within the scope of the invention.

Certain compounds disclosed herein can exist in unsolvated forms as wellas solvated forms, including hydrated forms. In general, the solvatedforms are equivalent to unsolvated forms and are encompassed within thescope of the present invention. Certain compounds disclosed herein mayexist in multiple crystalline or amorphous forms. In general, allphysical forms are equivalent for the uses contemplated by the presentinvention and are intended to be within the scope of the presentinvention.

As set out above, certain embodiments of the present compounds maycontain a basic functional group, such as amino or alkylamino, and are,thus, capable of forming pharmaceutically acceptable salts withpharmaceutically acceptable acids. The term “pharmaceutically acceptablesalts” in this respect, refers to the relatively non-toxic, inorganicand organic acid addition salts of compounds disclosed herein. Thesesalts can be prepared in situ during the final isolation andpurification of the compounds of the invention, or by separatelyreacting a purified compound of the invention in its free base form witha suitable organic or inorganic acid, and isolating the salt thusformed. Representative salts include the hydrobromide, hydrochloride,sulfate, bisulfate, phosphate, nitrate, acetate, valerate, oleate,palmitate, stearate, laurate, benzoate, lactate, phosphate, tosylate,citrate, maleate, fumarate, succinate, tartrate, napthylate, mesylate,glucoheptonate, lactobionate, and laurylsulphonate salts and the like.(See, for example, Berge et al. (1977) “Pharmaceutical Salts”, J. Pharm.Sci. 66:1-19.)

In other cases, the compounds disclosed herein may contain one or moreacidic functional groups and, thus, are capable of formingpharmaceutically acceptable salts with pharmaceutically acceptablebases. The term “pharmaceutically acceptable salts” in these instancesrefers to the relatively non-toxic, inorganic and organic base additionsalts of compounds disclosed herein. These salts can likewise beprepared in situ during the final isolation and purification of thecompounds, or by separately reacting the purified compound in its freeacid form with a suitable base, such as the hydroxide, carbonate orbicarbonate of a pharmaceutically acceptable metal cation, with ammonia,or with a pharmaceutically acceptable organic primary, secondary ortertiary amine. Representative alkali or alkaline earth salts includethe lithium, sodium, potassium, calcium, magnesium, and aluminum saltsand the like. Representative organic amines useful for the formation ofbase addition salts include ethylamine, diethylamine, ethylenediamine,ethanolamine, diethanolamine, piperazine and the like. (See, forexample, Berge et al., supra)

The terms “antagonist” and “inhibitor” are used interchangeably to referto an agent that decreases or suppresses a biological activity, such asto repress an activity of an ion channel, such as TRPA1. TRPA1inhibitors include inhibitors having any combination of the structuraland/or functional properties disclosed herein.

An “effective amount” of, e.g., a TRPA1 antagonist, with respect to thesubject methods of inhibition or treatment, refers to an amount of theantagonist in a preparation which, when applied as part of a desireddosage regimen brings about a desired clinical or functional result.Without being bound by theory, an effective amount of a TRPA1 antagonistfor use in the methods of the present invention, includes an amount of aTRPA1 antagonist effective to decrease one or more in vitro or in vivofunctions of a TRPA1 channel. Exemplary functions include, but are notlimited to, membrane polarization (e.g., an antagonist may promotehyperpolarization of a cell), ion flux, ion concentration in a cell,outward current, and inward current. Compounds that antagonize TRPA1function include compounds that antagonize an in vitro or in vivofunctional activity of TRPA1. When a particular functional activity isonly readily observable in an in vitro assay, the ability of a compoundto inhibit TRPA1 function in that in vitro assay serves as a reasonableproxy for the activity of that compound. In certain embodiments, aneffective amount is an amount sufficient to inhibit a TRPA1-mediatedcurrent and/or the amount sufficient to inhibit TRPA1 mediated ion flux.

The term “preventing,” when used in relation to a condition, such as alocal recurrence (e.g., pain), a disease such as cancer, a syndromecomplex such as heart failure or any other medical condition, is wellunderstood in the art, and includes administration of a compositionwhich reduces the frequency of, or delays the onset of, symptoms of amedical condition in a subject relative to a subject which does notreceive the composition. Thus, prevention of cancer includes, forexample, reducing the number of detectable cancerous growths in apopulation of patients receiving a prophylactic treatment relative to anuntreated control population, and/or delaying the appearance ofdetectable cancerous growths in a treated population versus an untreatedcontrol population, e.g., by a statistically and/or clinicallysignificant amount. Prevention of an infection includes, for example,reducing the number of diagnoses of the infection in a treatedpopulation versus an untreated control population, and/or delaying theonset of symptoms of the infection in a treated population versus anuntreated control population. Prevention of pain includes, for example,reducing the magnitude of, or alternatively delaying, pain sensationsexperienced by subjects in a treated population versus an untreatedcontrol population.

The term “prodrug” is intended to encompass compounds that, underphysiological conditions, are converted into the therapeutically activeagents of the present invention. A common method for making a prodrug isto include selected moieties that are hydrolyzed under physiologicalconditions to reveal the desired molecule. In other embodiments, theprodrug is converted by an enzymatic activity in the host animal.

The terms “TRPA1”, “TRPA1 protein”, and “TRPA1 channel” are usedinterchangeably throughout the application. These terms refer to an ionchannel (e.g., a polypeptide) comprising the amino acid sequence setforth in SEQ ID NO: 1, SEQ ID NO:3, or SEQ ID NO: 5 of WO 2007/073505,or an equivalent polypeptide, or a functional bioactive fragmentthereof. In certain embodiments, the term refers to a polypeptidecomprising, consisting of, or consisting essentially of, the amino acidsequence set forth in SEQ ID NO: 1, SEQ ID NO:3, or SEQ ID NO: 5. TRPA1includes polypeptides that retain a function of TRPA1 and comprise (i)all or a portion of the amino acid sequence set forth in SEQ ID NO: 1,SEQ ID NO:3 or SEQ ID NO: 5; (ii) the amino acid sequence set forth inSEQ ID NO: 1, SEQ ID NO:3 or SEQ ID NO: 5 with 1 to about 2, 3, 5, 7,10, 15, 20, 30, 50, 75 or more conservative amino acid substitutions;(iii) an amino acid sequence that is at least 70%, 75%, 80%, 90%, 95%,96%, 97%, 98%, or 99% identical to SEQ ID NO: 1, SEQ ID NO:3 or SEQ IDNO: 5; and (iv) functional fragments thereof. Polypeptides of theinvention also include homologs, e.g., orthologs and paralogs, of SEQ IDNO: 1, SEQ ID NO: 3 or SEQ ID NO: 5.

Exemplary compounds are shown below. The IC₅₀ values presented in Tables1-XX were obtained from patch clamp experiments, using human TRPA1, asdescribed in Example 2. An “A” indicates an IC₅₀ value less than orequal to 100 nM; a “B” indicates an IC₅₀ value of greater than 100 nMand less than 500 nM; a “C” indicates an IC₅₀ value of 500 nM to 1000nM; a “D” indicates an IC₅₀ value greater than 1000 nM. Metabolicstability in rat liver microsomes can be determined using techniquesdescribed in Kuhnz et al., Drug Metabolism and Disposition (1998) Vol.26, 1120-27. Oral bioavailability (expressed as % F) can be determinedas described in Basic & Clinical Pharmacology, 8th edition, Bertram G.Katzung (editor), Lange Medical Books/McGraw-Hill, 2001.

Compound ID R4 Activity 1 3-OCH2cPr A 2 3-OCH2CH═CH2 A 3 3-OEt A 43-OCF2H A 5 3-OMe A 6 3-OCH2CH2OCH3 A 7 2-OH-5-OMe A 8 2-F-5-OMe A 92-Br A 10 2-Br-5-OMe A 11 3-Cl A 12 3-CN A 13 H A 14 2-F-5-Cl A 15 2-OHA 16 2,6-diCl B 17 3,5-diOMe B 18 2,3-diCl B 19 2-Br-5-OH B 20 2-F B 213-NO2 B 22 3-OCH2CH2CH2OCH3 B 23 3-OCH2O-4 B 24 3,4,5-triF B 25 3-OCF3 B26 3-OH B 27 2,3-naphthalene B 28 2-CF3 B 29 4-OMe B 30 3-OCH2CH2OH B 312-Et B 32 3-F-4-Cl B 33 3-Py* C 34 3,4-diCl C 35 4-CN C 36 2-Cl C 374-NO2 C 38 4-Me D 39 3-Br-4-OMe D 40 2-OMe D 41 4-F D 42 2,5-diOMe D 432-OEt D 44 3-OMe-4-OH D 45 3,4-diF D 46 4-heptanyl D 47 3-OBu D 483-OiPr D 49 4-NMe2 D 50 3-OCH2CH2NMe2 D 51 3-OCH2CH2NH2 D 522-OCH2CH═CH2 53 4-Cl

Compound ID R Activity 101 1-Cl A 102 H B 103 2-Cl D 104 1-OH D 105 2-OHD 106 3-OH D 107 2-Me C

Compound ID R Activity 201 H A 202 1-OH D 203 2-OH D 204 3-OH D 2053-OMe B

Compound ID R1 R3 R4 R5 Activity 301 H H H H A 302 Me H H H A 303 H Me HH D 304 Me Me H H D 305 H H OCH2CH═CH2 H A 306 Me H OCH2CH═CH2 H A 307 HH CN H A 308 Me H CN H A 309 H Me CN H D 310 H H OEt H A 311 Me H OEt HA 312 H H H OH 313 Me H H OH D

Compound ID R Activity 401 2-F-3-OCH2CH═CH2 A 402 3-CHFCH2CH═CH2 A 4033-F-5-OCH2CH═CH2 A 404 2,5-diF-3-OPr A 405 3-OCH2CH═CH2 A 4063-Cl-5-OCH2CH═CH2 A 407 3-OPr A 408 3-OBu A 409 2-F-3-OEt A 4102-F-3-OPr 411 2-Cl-3-OCH2CH═CH2 A 412 3-OEt B 413 3-OCH2CF3 B 4143-OCF2H B 415 2-Cl-5-OCH2CH═CH2 B 416 3-OCH2C═CH B 417 2-F-5-OCH2CH═CH2B 418 3-OCH2CH2CH2OMe B 419 2-Cl, 3-OCH2(c-Pr) B 420 2,6-DiF-3-OEt B 4212-Me-3-OCH2CH═CH2 B 422 3-OCH2cPr B 423 2-Cl-3-OEt C 424 3-OMe C 4253-OCH2CN 426 2-Cl C 427 3-Bu C 428 2-Cl-3-OMe D 429 2-Cl-5-OMe D 4303-CN D 431 3-Cl D 432 2-F-5-OMe D 433 2-Br-5-OMe D 434 H D 435 2-OH D436 3-OH D 437 3-OiPr D 438 2,3-diOMe D 439 2-OCH2O-3- D 440 2-OCF2O-3-D 441 2,5-diOMe D 442 4-Cl D 443 3-N(Et)Ac D 444 3-NH2 D 445 3-NMe2 D446 2,3-diCl D 447 2-F D 448 2-Cl-5-CF3 D 449 2,6-di-Cl D 450 3-OCF2CH3D 451 3-OCF2CHF2 D 452 3-CF3 D 453 3-CH2OCH3 D 454 2-CF3-3-OCH2CH═CH2 D455 2-OMe-3-OCH2CH═CH2 D 456 2-OH-3-OCH2CH═CH2 D 457 3-OCH2O-4 D 4583,5-diOMe D 459 3-OC(O)cPr D 460 3-O-(n-pentyl) D 461 3-OCH2(c-Bu) D 4623-OCH2CH2OMe B

Compound ID Number R Activity 501

D 502

D 503

D 504

C 505

D 506

D 507

D

Compound ID R4 R1 Activity 601 3-OEt CH2CN A 602 3-OEt H B 603 3-OEt MeA 604 3-OEt Et A 605 3-OEt CH2CF3 C 606 3-OEt Bn A 607 3-OEt CH2(4-F-Ph)B 608 3-OEt CH2CO2Et A 609 3-OEt CH2CO2tBu C 610 3-OEt CH2CO2H D 6113-OEt CH2(2-Py) D 612 3-OEt CH2(3-Py) B 613 3-OEt CH2(4-Py) D 614 3-OEtCH2CH═CH2 B 615 3-OPr CH2CN A 616 2-F-3-OEt H A 617 2-F-3-OEt CH2CN A3-OCF2H H B 618 3-OCF2H CH2CN A 619 3-OCF2H Et B 620 3-OCF2H Bn A 6213-OMe H C 622 3-OMe Me B 623 3-OMe Et B 624 3-OMe Pr D 625 3-OMe Bn B626 3-OMe CH2CH2OH D 627 3-OMe CH2CH2OCH3 B 628 3-OMe CH2CH2NMe2 D 6293-OCH2CH═CH2 Me A 630 3-OCH2CH═CH2 Et A 631 3-OCH2CH═CH2 CH2CO2Et A 6323-OCH2CH═CH2 Bn A 633 3-OCH2CH═CH2 CH2(4-F-Ph) A 634 3-OCH2CH═CH2CH2(3-Py) A 635 3-OCH2CH═CH2 CH2(4-Py) D 636 3-OCH2CH═CH2 CH2(2-Py) B637 2-C1-5-OCH2CH═CH2 H B 638 2-C1-5-OCH2CH═CH2 Me A 6392-C1-3-OCH2CH═CH2 Me A 640 2-C1-3-OCH2CH═CH2 H A 641 3-OCH2cPr Me B 6422-CF3-3-OCH2CH═CH2 H D 643 2-CF3-3-OCH2CH═CH2 Me D 644 3-CN Me D 6453-OPr Me A 646 3-OPr Et A 647 3-OPr Bn A 648 2,6-DiF-3-OPr CH2CN A 6493-OCF2CH═CH2 Bn D

Compound ID Substituents Activity 800 A = CH B B = CH D = CH E = N X = F801 A = N D B = CH D = CH E = CH X = F 802 A = CH B B = CH D = CH E = NX = H 803 A = N D B = CH D = CH E = CH X = H 804 A = CH C B = CH D = N E= CH X = H 805 A = CH B B = N D = CH E = CH X = H 806 A = N C B = CH D =CH E = N X = H

RLM Compound T1/2 ID R Activity (min) 901 2-F-3-OEt B A 902 3-OEt B A903 3-Bu B 904 3-OPr A 905 3-CHFCH2CH═CH2 A A 906 3-SPr B A 907 3-CHFPrA A 908 3-CH(OH)Pr B A 909 3-C(═O)Pr B A 910 3-S(═O)Pr D 911 3-S(═O)2PrD 912 2,6-DiF-3-OPr A 913 OCH2CH2CH2OMe

Compound ID Substituents Activity 914 A = CH B B = CH D = CH E = CH 915A = N D B = CH D = CH E = CH 916 A = CH D B = N D = CH E = CH 917 A = CHD B = CH D = N E = CH 918 A = CH D B = CH D = CH E = N

Compound ID R4 R1 R3 R5 Activity 950 3-OCH2CH═CH2 H H H D 951 3-OCH2cPrH H H D 952 3-OCH2cPr H Me H D 953 3-OCH2cPr H Me Cl D 954 3-OCH2cPr H HCl D 955 3-CN H H H D 956 H H H H D 957 2-Cl-3-OCH2cPr H H H D 9583-OCH2cBu H H H D 959 3-OiBu H H H D 960 3-OPr H H H D 961 3-OCH2CH═CH2Bn H H D

It is believed that the more potent enantiomer is the beta form, whichhas the R configuration in the compound shown immediately below.

For each compound disclosed herein, it is believed that the enantiomericform having the stereochemistry illustrated above is more active thanthe other enantiomer. The enantiomerically pure compounds were preparedby separating the racemic mixture on a chiral column or by convertingthe racemic mixture into a mixture of diastereomers using an auxiliarychiral moiety, separating the diastereomers on a non-chiral column, thenhydrolyzing to remove the auxiliary chiral moiety.

Indications

Cellular homeostasis is a result of the summation of regulatory systemsinvolved in, amongst other things, the regulation of ion flux andmembrane potential. Cellular homeostasis is achieved, at least in part,by movement of ions into and out of cells across the plasma membrane andwithin cells by movement of ions across membranes of intracellularorganelles including, for example, the endoplasmic reticulum,sarcoplasmic reticulum, and mitochondria and endocytic organellesincluding endosomes and lysosomes.

Movement of ions across cellular membranes is carried out by specializedproteins. TRP channels are one large family of non-selective cationchannels that function to help regulate ion flux and membrane potential.TRP channels are subdivided into 6 sub-families including the TRPA(ANKTM1) family, and TRPA1 is a member of the TRPA class of TRPchannels.

Non-selective cation channels such as TRPA1 modulate the flux of calciumand sodium ions across cellular membranes. Sodium and calcium influxleads to depolarization of the cell. This increases the probability thatvoltage-gated ion channels will reach the threshold required foractivation. As a result, activation of non-selective cation channels canincrease electrical excitability and increase the frequency ofvoltage-dependent events. Voltage-dependent events include, but are notlimited to, neuronal action potentials, cardiac action potentials,smooth muscle contraction, cardiac muscle contraction, and skeletalmuscle contraction.

Calcium influx caused by the activation of non-selective cation channelssuch as TRPA1 also alters the intracellular free calcium concentration.Calcium is a ubiquitous second messenger molecule within the cell, soalterations in intracellular calcium levels have profound effects onsignal transduction and gene expression. As a result, activation ofnon-selective cation channels such as TRPA1 can lead to changes in geneexpression and cellular phenotype. Gene expression events include, butare not limited to, production of mRNAs encoding cell surface receptors,ion channels, and kinases. These changes in gene expression can lead tohyperexcitability in that cell.

TRPA1 proteins are broad receptors for noxious chemicals, bothendogenous and exogenous. They respond to any of a variety of stimulithat can induce cysteine modification (Hinman et al., 2006; MacPhersonet al. 2007). In addition TRPA1 can function as a receptor operatedchannel. It expressed in sensory neurons (see, e.g., Jordt et al. (2004)Nature 427:260-265) including those with cell bodies residing in thedorsal root ganglion, trigeminal ganglion, and nodose ganglia (see Jordtet al. (2004) Nature 427:260-265, Nagata et al. (2005) J. Neurosci25(16) 4052-61). In addition, low levels of TRPA1 message can be foundin some types of fibroblasts (see Jaquemar et al. (1999) JBC 274(11):7325-33). TRPA1 has also been reported to be expressed in the bladder.Stimulation of a number of extracellular receptors, including, but notlimited to, G-protein coupled receptors or receptor tyrosine kinases aresufficient to activate TRPA1.

Modulating the function of TRPA1 proteins provides a means of modulatingcalcium homeostasis, sodium homeostasis, membrane polarization, and/orintracellular calcium levels, and compounds that can modulate TRPA1function are useful in many aspects, including, but not limited to,maintaining calcium homeostasis, modulating intracellular calciumlevels, modulating membrane polarization, and treating or preventingdiseases, disorders, or conditions associated with calcium and/or sodiumhomeostasis or dyshomeostasis.

Thus, TRPA1 antagonists can be used as part of a prophylaxis ortreatment for a variety of disorders and conditions, described in moredetail below. In other embodiments, the invention provides methods andcompositions for inhibiting a function of a TRPA1 channel in vitro or invivo. The compounds described herein can be used in the treatment of anyof the foregoing or following diseases or conditions, including in thetreatment of pain associated with any of the foregoing or followingdiseases or conditions.

Treatment of Pain, Sensitivity to Pain and Touch, or Pain-RelatedDiseases or Disorders

In certain embodiments, the TRPA1 inhibitor is used to treat orameliorate pain. Exemplary classes of pain that can be treated using aTRPA1 inhibitor include, but are not limited to nociceptive pain,inflammatory pain, and neuropathic pain. The pain can be chronic oracute.

As outlined above, TRPA1 inhibitors may be particularly useful in thetreatment of pain associated with cancer, osteoarthritis, rheumatoidarthritis, post-herpetic neuralgia, burns, and other indicationsdetailed above. To further illustrate, additional exemplary indicationsfor which compounds disclosed herein can be used include oral pain,pelvic pain, Fabry's disease, complex regional pain syndrome,pancreatitis, and fibromyalgia syndrome.

Fabry's Disease

Vague complaints of pain in hands and feet may be a presenting feature.These symptoms are called acroparesthesias, as they reflect theperipheral neuropathy that is a frequent manifestation of the disease.This pain may be both episodic and chronic. Acute episodes may betriggered by exposure to extremes of temperature, stress, emotion,and/or fatigue.

The compounds disclosed herein may also be used in connection withprevention or treatment of sensitivity to pain and touch. Pain orsensitivity to pain and touch may be indicated in a variety of diseases,disorders or conditions, including, but not limited to, diabeticneuropathy, breast pain, psoriasis, eczema, dermatitis, burn,post-herpetic neuralgia (shingles), nociceptive pain, peripheralneuropathic and central neuropathic pain, chronic pain, cancer and tumorpain, spinal cord injury, crush injury and trauma induced pain,migraine, cerebrovascular and vascular pain, sickle cell disease pain,rheumatoid arthritis pain, musculoskeletal pain including treating signsand symptoms of osteoarthritis and rheumatoid arthritis, orofacial andfacial pain, including dental, temperomandibular disorder, and cancerrelated, lower back or pelvic pain, surgical incision related pain,inflammatory and non-inflammatory pain, visceral pain, psychogenic painand soft tissue inflammatory pain, fibromyalgia-related pain, and reflexsympathetic dystrophy, and pain resulting from kidney stones or urinarytract infection.

Oral pain is a particular category of pain that may be treated using theTRPA1 inhibitors disclosed herein. The term “oral pain” refers to anypain in the mouth, throat, lips, gums, teeth, tongue, or jaw. The termis used regardless of the cause of the pain and regardless of whetherthe oral pain is a primary or secondary symptom of a particular disease,injury, or condition.

Oral pain has a large number of possible causes. In certain embodiments,oral pain is caused by an injury or disease of the mouth, jaw, teeth,gums, throat, lips, or tongue. In certain other embodiments, oral painis a consequence of an injury or disease that primarily affects anotherpart of the body. In still other embodiments, oral pain is a side effectof a therapy used to treat an injury or disease of the mouth or anotherpart of the body. TRPA1 inhibitors are useful in treating oral painregardless of its cause.

In certain embodiments, oral pain is caused by ulcers, sores, or otherlesions in the mouth. For example, oral pain may be caused by ulcers,sores, or other lesions on the tongue, gums, lips, throat, or othertissues of the mouth. Alternatively or additionally, oral pain may becaused by inflammation of the throat, tongue, gums, lips, or othertissues of the mouth. Inflammation may accompany ulcers or otherlesions, or inflammation may occur prior to or in the absence offormation of ulcers or other lesions.

The foregoing are merely exemplary of diseases and conditions that causeor lead to inflammation, lesions, ulcers, or other sources of oral pain.In other embodiments, the oral pain is due to an injury to the mouth,jaw, lips, gums, or teeth. In other embodiments, the oral pain is due tooral surgery, for example, surgery for cancer, tooth extraction, or jawremodeling. Other conditions that may lead to oral ulcers, and thus oralpain, include, but are not limited to chickpox, herpes zoster,infectious mononucleosis, syphilis, tuberculosis, acute necrotizinggingivitis, and burning mouth syndrome.

Fibromyalgia (FMS; fibromyalgia syndrome) is a widespreadmusculoskeletal pain and fatigue disorder. Fibromyalgia is characterizedby pain in the muscles, ligaments, and tendons. The condition affectsmore women than men, and occurs in people of all ages. Overall, FMS isestimated to afflict 3-6% of the population. Patients have described thepain associated with fibromyalgia as deep muscular aching, throbbing,shooting, and stabbing. The pain sometimes includes an intense burningsensation. The pain and stiffness are often worse in the morning orafter repetitive use of a particular muscle group.

Additionally, varying levels of fatigue ranging from mild toincapacitating are often associated with fibromyalgia. Other symptoms offibromyalgia include gastrointestinal symptoms. Irritable bowel syndromeand IBS-like symptoms such as constipation, diarrhea, frequent abdominalpain, abdominal gas, and nausea occur in roughly 40 to 70% of FMSpatients. Acid reflux or gastroesophogeal reflux disease (GERD) occursat a similar frequency.

Another frequent and debilitating symptom of FMS is chronic headaches,including migraine and tension-type headaches. Such headaches areexperienced by approximately 70% of FMS patients. Additionally, FMSpatients often experience temporomandibular joint dysfunction syndrome(also known as TMJ) which produces pain in the jaw, teeth, and mouth.TMJ may also exacerbate headaches. Other common symptoms of FMS include,but are not limited to, premenstrual syndrome and painful periods; chestpain; morning stiffness; cognitive or memory impairment; numbness andtingling sensations; muscle twitching; irritable bladder; the feeling ofswollen extremities; skin sensitivities; dry eyes and mouth; dizziness;and impaired coordination. Additionally, patients are often sensitive toodors, loud noises, and bright lights.

The impact of FMS on the patient is directly correlated with the levelof pain and fatigue. Pain may be so severe as to interfere with normalwork or family functioning. There is currently no cure for FMS, andcurrent therapies focus primarily on improving sleep (to decreasefatigue) and treating pain. Compounds disclosed herein could be used tohelp manage the pain associated with FMS. Such pain includes, but is notlimited to, oral pain in the jaw, teeth, and mouth. Such pain alsoincludes non-oral musco-skeletal pain, pain due to headaches, and paindue to gastrointestinal symptoms.

Complex Regional Pain Syndrome (CRPS; also known as chronic regionalpain syndrome) is a chronic pain condition. CRPS was formerly known asreflex sympathetic dystrophy (RSD). CRPS is a chronic, painful, andprogressive neurological condition that affects skin, muscles, joints,and bones. The syndrome usually develops in an injured limb, such as abroken leg or following surgery. However, many cases involve only aminor injury, such as a sprain, and somtimes no precipitating injuriousevent can be identified. CRPS involves continuous, intense pain that isdisproportionate to the severity of the injury. The pain worsens, ratherthan improves, over time.

The compounds disclosed herein can also be used to treat endometriosisand the pain associated therewith.

In addition, pain associated with cancer or with cancer treatment is asignificant cause of chronic pain. Cancers of the bone, for example,osteosarcoma, are considered exceptionally painful, and patients withadvanced bone cancer may require sedation to tolerate the intense andpersistent pain. Accordingly, TRPA1 antagonists of the inventionrepresent a significant possible therapeutic for the treatment of pain,for example, the pain associated with cancer or with cancer treatment.

Respiratory Disorders

The compounds described herein are useful for the treatment orprevention of respiratory conditions. Such conditions affect the lung,pleural cavity, bronchial tubes, trachea, upper respiratory tract aswell as the nerves and muscles involved in breathing. Respiratorydiseases that may be treated with the compounds described herein includeobstructive diseases such as chronic obstructive pulmonary disease(COPD), emphysema, chronic bronchitis, asthma (including asthma causedby industrial irritants), cystic fibrosis, bronchiectasis,bronchiolitis, allergic bronchopulmonary aspergillosis, andtuberculosis; restrictive lung disease including asbestosis, radiationfibrosis, hypersensitivity pneumonitis, infant respiratory distresssyndrome, idiopathic pulmonary fibrosis, idiopathic pulmonary fibrosis,idiopathic interstial pneumonia sarcoidosis, eosinophilic pneumonia,lymphangioleiomyomatosis, pulmonary Langerhan's cell histiocytosis, andpulmonary alveolar proteinosis; respiratory tract infections includingupper respiratory tract infections (e.g., common cold, sinusitis,tonsillitis, pharyngitis and laryngitis) and lower respiratory tractinfections (e.g., pneumonia); respiratory tumors whether malignant(e.g., small cell lung cancer, non-small cell lung cancer,adenocarcinoma, squamous cell carcinoma, large cell undifferentiatedcarcinoma, carcinoid, mesothelioma, metastatic cancer of the lung,metastatic germ cell cancer, metastatic renal cell carcinoma) or benign(e.g., pulmonary hamartoma, congenital malformations such as pulmonarysequestration and congenital cystic adenomatoid malformation (CCAM));pleural cavity diseases (e.g., empyema and mesothelioma); and pulmonaryvascular diseases (e.g, pulmonary embolism such as thromboembolism, andair embolism (iatrogenic), pulmonary arterial hypertension, pulmonaryedema, pulmonary hemorrhage, inflammation and damage to capillaries inthe lung resulting in blood leaking into the alveoli. Other conditionsthat may be treated include disorders that affect breathing mechanics(e.g., obstructive sleep apnea, central sleep apnea, amyotrophic lateralsclerosis, Guillan-Barre syndrome, and myasthenia gravis). The presentcompounds can also be useful for treating, reducing, or preventing oneor more symptoms associated with respiratory conditions including, forexample, shortness of breath or dyspnea, cough (with or without theproduction of sputum), coughing blood (haemoptysis), chest painincluding pleuritic chest pain, noisy breathing, wheezing, and cyanosis.Other conditions include allergy-induced cough and angiotensinconverting enzyme inhibitor (ACEI) induced cough.

Dermatological Diseases or Disorders

Influx of calcium across plasma membrane of skin cells is a criticalsignaling element involved in cellular differentiation in the skinepidermis (Dotto, 1999 Crit Rev Oral Biol Med 10:442-457). Regulating ormodulating the calcium entry pathway, and thus a critical control pointfor skin cell growth, can treat or prevent skin diseases or disordersthat are characterized by epidermal hyperplasia, a condition in whichskin cells both proliferate too rapidly and differentiate poorly. Suchdiseases include psoriasis, and basal and squamous cell carcinomas.

Psoriasis, estimated to affect up to 7 million Americans, afflictssufferers with mild to extreme discomfort, enhanced susceptibility tosecondary infections, and psychological impact due to disfigurement ofthe affected areas (Lebwohl and Ali, 2001 J Am Acad Dermatol45:487-498). Basal cell carcinomas (BCC) and squamous cell carcinomas(SCC) of the skin represent at least one-third of all cancers diagnosedin the United States each year. More than 1 million new cases arereported annually and incidence is increasing. Despite being relativelynon-aggressive, slow-growing cancers, BCCs are capable of significantlocal tissue destruction and disfigurement. SCCs are more aggressive andthus present even greater complications.

Many dermatological disorders are accompanied by itch (pruritus).Pruritus and pain share many mechanistic similarities. Both areassociated with activation of C-fibers, both are potentiated byincreases in temperature and inflammatory mediators and both can bequelled with opiates. Decreasing neuronal excitability, particularlyC-fiber excitability may alleviate pruritus associated with dialysis,dermatitis, pregnancy, poison ivy, allergy, dry skin, chemotherapy andeczema.

Neurological or Neurodegenerative Diseases and Disorders

Neurodegenerative diseases and disorders include but are not limited toAlzheimer's disease (AD), Parkinson's disease, Huntington's disease,amyotrophic lateral sclerosis (ALS), and other brain disorders caused bytrauma or other insults including aging.

Mechanisms associated with calcium signaling may be altered in manyneurodegenerative diseases and in disorders resulting from brain injury.For example, fibroblasts or T-lymphocytes from patients with AD haveconsistently displayed an increase in Ca²⁺ release from intracellularstores compared to controls (Ito et al. (1994) Proc. Natl. Acad. Sci.U.S.A. 91:534-538; Gibson et al. (1996) Biochem. Biophys. ACTA1316:71-77; Etchenberrigaray et al. (1998) Neurobiology of Disease,5:37-45). Consistent with these observations, mutations in presenilingenes (PS1 or PS2) associated with familial AD (FAD) have been shown toincrease InsP3-mediated Ca²⁺ release from internal stores (Guo et al.(1996) Neuro Report, 8:379-383; Leissring et al. (1999) J.Neurochemistry, 72:1061-1068; Leissring et al. (1999) J. Biol. Chem.274(46):32535-32538; Leissring et al. (2000) J. Cell Biol.149(4):793-797; Leissring et al. (2000) Proc. Natl. Acad. Sci. U.S.A.97(15):8590-8593). Furthermore, mutations in PS1 or PS2 associated withan increase in amyloidogenic amyloid f3 peptide generation in AD arereported to be associated with a decrease in intracellular calcium level(Yoo et al. (2000) Neuron, 27(3):561-572).

Experimental traumatic brain injury has been shown to initiate massivedisturbances in Ca²⁺ concentrations in the brain that may contribute tofurther neuronal damage. Intracellular Ca²⁺ may be elevated by manydifferent ion channels. It has been further shown that channel blockersmay be beneficial in the treatment of neurological motor dysfunctionwhen administered in the acute posttraumatic period (Cheney et al.(2000) J. Neurotrauma, 17(1):83-91).

Inflammatory Diseases and Disorders

Compositions and methods provided herein may also be used in connectionwith treatment of inflammatory diseases. These diseases include but arenot limited to asthma, chronic obstructive pulmonary disease, rheumatoidarthritis, osteoarthritis, inflammatory bowel disease,glomerulonephritis, neuroinflammatory diseases such as multiplesclerosis, and disorders of the immune system.

The activation of neutrophils (PMN) by inflammatory mediators is partlyachieved by increasing cytosolic calcium concentration ([Ca^(2+]) _(i)).Certain calcium channel-mediated calcium influx in particular is thoughtto play an important role in PMN activation. It has been shown thattrauma increases PMN store-operated calcium influx (Hauser et al. (2000)J. Trauma Injury Infection and Critical Care 48 (4):592-598) and thatprolonged elevations of [Ca²⁺]_(i), due to enhanced store-operatedcalcium influx may alter stimulus-response coupling to chemotaxins andcontribute to PMN dysfunction after injury. Modulation of PMN [Ca²⁺]_(i)through store-operated calcium channels might therefore be useful inregulating PMN-mediated inflammation and spare cardiovascular functionafter injury, shock or sepsis (Hauser et al. (2001) J. Leukocyte Biology69 (1):63-68).

Peripheral neuropathy, for example diabetic neuropathy, is a particularcondition that involves both a neuronal and an inflammatory component.Without being bound by a mechanistic theory, the TRPA1 antagonists ofthe invention may be useful in treating peripheral neuropathiesincluding, but not limited to, diabetic neuropathy. In addition to theiruse in the treatment of peripheral neuropathies (e.g., reducinginflammation), the subject inhibitors may also be useful in reducing thepain associated with peripheral neuropathy.

Neurogenic inflammation often occurs when neuronal hyperexcitabilityleads to the release of peptides that trigger inflammation. Thesepeptides include substance P and CGRP. Blocking TRPA1 would reduceneuronal activity and thus could block neurogenic inflammation.

Pancreatitis is an inflammation of the pancreas. The pancreas is a largegland behind the stomach and close to the duodenum. Normally, digestiveenzymes do not become active until they reach the small intestine, wherethey begin digesting food. But if these enzymes become active inside thepancreas, they start “digesting” the pancreas itself.

Acute pancreatitis is usually, although not exclusively, caused bygallstones or by alcohol abuse. Acute pancreatitis usually begins withpain in the upper abdomen that may last for a few days. The pain may besevere and may become constant. The pain may be isolated to the abdomenor it may reach to the back and other areas. Sometimes, and for somepatients, the pain is sudden and intense. Other times, or for otherpatients, the pain begins as a mild pain that worsens after eating.Someone with acute pancreatitis often looks and feels very sick. Othersymptoms may include swollen and tender abdomen, nausea, vomiting,fever, and rapid pulse. Severe cases of acute pancreatitis may causedehydration and low blood pressure, and may even lead to organ failure,internal bleeding, or death.

During acute pancreatitis attacks, the blood levels of amylase andlipase are often increased by at least 3-fold. Changes may also occur inblood levels of glucose, calcium, magnesium, sodium, potassium, andbicarbonate.

The current treatment depends on the severity of the attack. Treatment,in general, is designed to support vital bodily functions, manage pain,and prevent complications. Although acute pancreatitis typicallyresolved in a few days, pain management during an attack is oftenrequired. The compounds disclosed herein can be used to relieve the painassociated with acute pancreatitis.

Chronic pancreatitis—If injury to the pancreas continues, chronicpancreatitis may develop. Chronic pancreatitis occurs when digestiveenzymes attack and destroy the pancreas and nearby tissues, causingscarring and pain. Chronic pancreatitis may be caused by alcoholism, orby blocked, damaged, or narrowed pancreatic ducts. Additionally,hereditary factors appear to influence the disease, and in certaincases, there is no identifiable cause (so called idiopathicpancreatitis).

Most people with chronic pancreatitis have abdominal pain. The pain mayget worse when eating or drinking, spread to the back, or becomeconstant and disabling. Other symptoms include nausea, vomiting, weightloss, and fatty stools.

Relieving pain is the first step in treating chronic pancreatitis. Oncethe pain has been managed, a high carbohydrate and low fat dietary planis put in place. Pancreatic enzymes may be used to help compensate fordecrease enzyme production from the injured pancreas. Sometimes insulinor other drugs are needed to control blood glucose.

Although pain is typically managed using drug therapy, surgery may benecessary to relieve pain. Surgery may be necessary to drain an enlargedpancreatic duct or even to removing a portion of a seriously injuredpancreas.

Pain is frequently present with chronic pancreatitis. For example, painis present for approximately 75% of patients with alcoholic chronicpancreatitis, 50% of patients with late-onset idiopathic chronicpancreatitis, and 100% of patients with early-onset idiopathic chronicpancreatitis (DiMagno, 1999, Gastroenterology 116(5): 1252-1257).

A minority of patients with pain have readily identifiable lesions whichare relatively easy to treat surgically or endoscopically. In otherpatients, pain is often thought to result from a variety of causes,including elevated intrapancreatic pressure, ischemia, and fibrosis.Without being bound by theory, however, these phenomena are not likelythe underlying cause of the pain. Rather, pain may result from abackground of neuronal sensitization induced by damage to theperineurium and subsequent exposure of the nerves to mediators andproducts of inflammation.

Given the importance of effective pain management in patients withchronic pancreatitis, additional therapies for treating painful symptomsare important and useful. The compounds disclosed herein can be used tomanage the pain associated with chronic pancreatitis; they can be usedalone or as part of an overall therapeutic treatment plan to managepatients with chronic pancreatits. For example, the compounds can beadministered with pancreatic enzymes and/or insulin as part of atherapeutic regimen designed to manage patients with chronicpancreatitis.

Cancer treatments are not only painful, but they may even be toxic tohealthy tissue. Some chemotherapeutic agents can cause painfulneuropathy. Accordingly, the compounds disclosed herein could representa significant possible therapeutic for the treatment of the pain and/orinflammation associated with cancer treatments that cause neuropathy.

A major function of prostaglandins is to protect the gastric mucosa.Included in this function is the modulation of intracellular calciumlevel in human gastric cells which plays a critical role in cellproliferation. Consequently, inhibition of prostaglandins bynonsteroidal anti-inflammatory drugs (NSAIDs) can inhibit calcium influxin gastric cells (Kokoska et al. (1998) Surgery (St Louis) 124(2):429-437). The NSAIDs that relieve inflammation most effectively alsoproduce the greatest gastrointestinal damage (Canadian Family Physician,January 1998, p. 101). Thus, the ability to independently modulatecalcium channels in specific cell types may help to alleviate such sideeffect of anti-inflammatory therapy. Additionally or alternatively,administration of TRPA1 inhibitory compounds disclosed herein may beused in combination with NSAIDs, thus promoting pain relief usingreduced dosage of NSAIDs.

Incontinence

Incontinence is a significant social and medical problem affecting bothmen and women. Incontinence has many causes including, but not limitedto, age, pregnancy, radiation exposure, surgery, injury, cancer,enlargement of the prostatic, prostatic hyperplasia, and diseases of thebladder or musculature that supports the urethra. The inventioncontemplates methods for treating incontinence due to any of theforegoing, as well as incontinence of unknown cause or continence due toanxiety, stress, or depression.

In certain embodiments, the compounds disclosed herein are used toreduce bladder hyperactivity by decreasing the activity of the neuronsthat innervate the bladder. In certain embodiments, incontinence isaccompanied by pain. For example, incontinence incident to bladdercystitis or incontinence incident to an injury may be accompanied bypain. When incontinence is accompanied by pain, the compound may beadministered to treat both incontinence and to reduce pain.

Animal models of incontinence are often associated with an increase inthe frequency of spontaneous action potentials and a chronicdepolarization of the smooth muscle cells. Evidence suggests that anon-selective cation current could lead to this depolarization. SinceTRPA1 mRNA is expressed in neurons that innervate bladder, blockingTRPA1 might be an effective treatment for incontinence. In addition,TRPA1 is activated by stimulation of the muscarinic type 1 acetylcholinereceptor (M1, see Jordt et al. (2004) Nature 427:260-265).Antimuscarininc agents are well known drugs for the treatment ofcondition such as overactive bladder. Thus blocking TRPA1, a downstreamtarget of the M1 receptor might alleviate such conditions without theside effects that are associated with muscarinic antagonists.

Temperature Regulation

Because of the effects of ion flux on arterial tension and relaxation,the subject compounds can also be used to affect thermal sensitivity.Furthermore, given that TRPA1 channels are thermal responsive channelsinvolved in the reception and sensation of cold stimuli, TRPA1antagonists can be used to modulate the sensation of cool, cold anddecreased temperatures that often accompany pain.

Allergies

Allergies can sometimes lead to canker sores and other oral lesions.Oral lesions due to an allergy may be more likely when a person's oraltissues come into contact with the causative allergen. However, contactbetween the allergen and oral tissue is not necessarily required toproduce an oral lesion. Exemplary allergens that can lead to orallesions include food allergens such as fruits and vegetables (e.g.,strawberries, lemons, oranges, pineapples, apples, figs, tomatoes);shellfish; chocolate; nuts; dairy (e.g., milk and cheese); cereal grains(e.g., buckwheat, wheat, oats, rye, barley, gluten protein found ingrains); additives (e.g., cinnamonaldehyde (a flavoring agent), benzoicacid (a preservative); toothpastes (e.g., some people have a sensitivityto sodium laurel sulfate found in certain toothpastes and mouthwashes);nonsteroidal anti-inflammatory drugs (NSAIDs; some people have asensitivity leading to canker sores in response to this class of drug).

The compounds disclosed herein can also be used to treat seasonalallergies, e.g., allergic rhinitis.

Combination Therapy

The subject compounds can be used alone or in combination with otherpharmaceutically active agents. Examples of such other pharmaceuticallyactive agents include, but are not limited to, anti-inflammatory agents(e.g., NSAIDS, bradykinin receptor antagonists, hormones and autacoidssuch as corticosteroids), anti-acne agents (e.g., retinoids),anti-wrinkle agents, anti-scarring agents, anti-incontinence agents(such as M1-receptor antagonists) anti-emetics (such as NK1antagonists), anti-psoriatic agents, antacids, anti-proliferative agents(e.g., anti-eczema agents, anti-cancer), anti-fungal agents, anti-viralagents, anti-septic agents (e.g., antibacterials), local anaesthetics,anti-migraine agents, keratolytic agents, hair growth stimulants, hairgrowth inhibitors, and other agents used for the treatment of skindiseases or conditions. Certain active agents belong to more than onecategory.

In certain embodiments, a compound of the invention is conjointlyadministered with an analgesic. Suitable analgesics include, but are notlimited to, opioids, glucocorticosteroids, non-steroidalanti-inflammatories, naphthylalkanones, oxicams, para-aminophenolderivatives, propionic acids, propionic acid derivatives, salicylates,fenamates, fenamate derivatives, pyrozoles, and pyrozole derivatives.Examples of such analgesic compounds include, but are not limited to,codeine, hydrocodone, hydromorphone, levorpharnol, morphine, oxycodone,oxymorphone, butorphanol, dezocine, nalbuphine, pentazocine, etodolac,indomethacin, sulindac, tolmetin, nabumetone, piroxicam, acetaminophen,fenoprofen, flurbiprofen, ibuprofen, ketoprofen, naproxen, diclofenac,oxaprozin, aspirin, diflunisal, meclofenamic acid, mefanamic acid,prednisolone, and dexamethasone. Preferred analgesics are non-steroidalanti-inflammatories and opioids (preferably morphine).

In some embodiments, the compounds disclosed herein can be admininsteredin conjunction with a therapeutic whose administration causes pain. Forexample, a TRPA1 antagonist can be administered in conjunction with ananesthetic, to reduce the pain caused by the administration of theanaesthetic. A TRPA1 antagonist can also be administered in conjunctionwith a chemotherapeutic agent, to reduce the pain caused byadministration of the chemotherapeutic agent.

In certain embodiments, a compound of the invention is conjointlyadministered with a non-steroidal anti-inflammatory. Suitablenon-steroidal anti-inflammatory compounds include, but are not limitedto, piroxicam, diclofenac, etodolac, indomethacin, ketoralac, oxaprozin,tolmetin, naproxen, flubiprofen, fenoprofen, ketoprofen, ibuprofen,mefenamic acid, sulindac, apazone, phenylbutazone, aspirin, celecoxiband rofecoxib.

In certain embodiments, a compound of the invention is conjointlyadministered with an antiviral agent. Suitable antiviral agents include,but are not limited to, amantadine, acyclovir, cidofovir, desciclovir,deoxyacyclovir, famciclovir, foscamet, ganciclovir, penciclovir,azidouridine, anasmycin, amantadine, bromovinyldeoxusidine,chlorovinyldeoxusidine, cytarbine, didanosine, deoxynojirimycin,dideoxycitidine, dideoxyinosine, dideoxynucleoside, edoxuidine,enviroxime, fiacitabine, foscamet, fialuridine, fluorothymidine,floxuridine, hypericin, interferon, interleukin, isethionate,nevirapine, pentamidine, ribavirin, rimantadine, stavirdine,sargramostin, suramin, trichosanthin, tribromothymidine,trichlorothymidine, vidarabine, zidoviridine, zalcitabine3-azido-3-deoxythymidine, 2′,3′-dideoxyadenosine (ddA),2′,3′-dideoxyguanosine (ddG), 2′,3′-dideoxycytidine (ddC),2′,3′-dideoxythymidine (ddT), 2′3′-dideoxy-dideoxythymidine (d4T),2′-deoxy-3′-thia-cytosine (3TC or lamivudime),2′,3′-dideoxy-2′-fluoroadenosine, 2′,3′-dideoxy-2′-fluoroinosine,2′,3′-dideoxy-2′-fluorothymidine, 2′,3′-dideoxy-2′-fluorocytosine,2′3′-dideoxy-2′,3′-didehydro-2′-fluorothymidine (Fd4T),2′3′-dideoxy-2′-beta-fluoroadenosine (F-ddA),2′3′-dideoxy-2′-beta-fluoro-inosine (F-ddI), and2′,3′-dideoxy-2′-beta-fluorocytosine (F-ddC), trisodiumphosphomonoformate, trifluorothymidine, 3′ azido-3′ thymidine (AZT),dideoxyinosine (ddI), and idoxuridine.

In certain embodiments, a compound of the invention is conjointlyadministered with an antibacterial agent. Suitable antibacterial agentsinclude, but are not limited to, amanfadine hydrochloride, amanfadinesulfate, amikacin, amikacin sulfate, amoglycosides, amoxicillin,ampicillin, amsamycins, bacitracin, beta-lactams, candicidin,capreomycin, carbenicillin, cephalexin, cephaloridine, cephalothin,cefazolin, cephapirin, cephradine, cephaloglycin, chilomphenicols,chlorhexidine, chloshexidine gluconate, chlorhexidine hydrochloride,chloroxine, chlorquiraldol, chlortetracycline, chlortetracyclinehydrochloride, ciprofloxacin, circulin, clindamycin, clindamycinhydrochloride, clotrimazole, cloxacillin, demeclocycline,diclosxacillin, diiodohydroxyquin, doxycycline, ethambutol, ethambutolhydrochloride, erythromycin, erythromycin estolate, erhmycin stearate,farnesol, floxacillin, gentamicin, gentamicin sulfate, gramicidin,giseofulvin, haloprogin, haloquinol, hexachlorophene, iminocylcline,iodochlorhydroxyquin, kanamycin, kanamycin sulfate, lincomycin,lineomycin, lineomycin hydrochloride, macrolides, meclocycline,methacycline, methacycline hydrochloride, methenine, methenaminehippurate, methenamine mandelate, methicillin, metonidazole, miconazole,miconazole hydrochloride, minocycline, minocycline hydrochloride,mupirocin, nafcillin, neomycin, neomycin sulfate, netimicin, netilmicinsulfate, nitrofurazone, norfloxacin, nystatin, octopirox, oleandomycin,orcephalosporins, oxacillin, oxyteacline, oxytetracycline hydrochloride,parachlorometa xylenol, paromomycin, paromomycin sulfate, penicillins,penicillin G, penicillin V, pentamidine, pentamidine hydrochloride,phenethicillin, polymyxins, quinolones, streptomycin sulfate,tetracycline, tobramycin, tolnaftate, triclosan, trifampin, rifamycin,rolitetracycline, spectinomycin, spiramycin, struptomycin, sulfonamide,tetracyclines, tetracycline, tobramycin, tobramycin sulfate,triclocarbon, triclosan, trimethoprim-sulfamethoxazole, tylosin,vancomycin, and yrothricin.

Examples of retinoids that be administered with the subject compounds,e.g., where the TRPA1 inhibitor can be used to reduce the pain and/orinflammatory effect of the retinoid, include, but are not limited to,compounds such as retinoic acid (both cis and trans), retinol,adapalene, vitamin A and tazarotene. Retinoids are useful in treatingacne, psoriasis, rosacea, wrinkles and skin cancers and cancerprecursors such as melanoma and actinic keratosis.

Similarly, the subject compounds can be used in conjunction withkeratolytic agents include benzoyl peroxide, alpha hydroxyacids, fruitacids, glycolic acid, salicylic acid, azelaic acid, trichloroaceticacid, lactic acid and piroctone.

The subject compounds can be used with anti-acne agents, anti-eczemaagents and anti-psoratic agents. Compounds particlarly useful intreating acne include azelaic acid (an aliphatic diacid with antiacneproperties), anthralin (a diphenolic compound with antifungal andantipsoriatic properties), and masoprocol (nordihydroguaiaretic acid, atetraphenolic compound with antioxidant properties, also useful in thetreatment of actinic keratosis) and analogs thereof (such asaustrobailignan 6, oxoaustrobailignan6,4′-O-methyl-7,7′-dioxoaustrobailignan 6, macelignan,demethyldihydroguaiaretic acid, 3,3′,4-trihydroxy-4′-methoxylignan,Saururenin, 4-hydroxy-3,3′,4′-trimethoxylignan, and isoanwulignan).Anti-eczema agents include pimecrolimus and tacrolimus. Anti-psoriaticactive agents suitable for use in the present invention includeretinoids (including isomers and derivatives of retinoic acid, as wellas other compounds that bind to the retinoic acid receptor, such asretinoic acid, acitretin, 13-cis-retinoic acid (isotretinoin),9-cis-retinoic acid, tocopheryl-retinoate (tocopherol ester of retinoicacid (trans- or cis-)), etretinate, motretinide,1-(13-cis-retinoyloxy)-2-propanone,1-(13-cis-retinoyloxy)-3-decanoyloxy-2-propanone,1,3-bis-(13-cis-retinoyloxy)-2-propanone,2-(13-cis-retinoyloxy)-acetophenone,13-cis-retinoyloxymethyl-2,2-dimethyl propanoate,2-(13-cis-retinoyloxy)-n-methyl-acetamide,1-(13-cis-retinoyloxy)-3-hydroxy-2-propanone,1-(13-cis-retinoyloxy)-2,3-dioleoylpropanone, succinimidyl13-cis-retinoate, adapalene, and tazarotene), salicylic acid(monoammonium salt), anthralin, 6-azauridine, vitamin D derivatives(including but not limited to Rocaltrol (Roche Laboratories), EB 1089(24α,26α,27α-trihomo-22,24-diene-1α,25-(OH)₂-D₃), KH 1060(20-epi-22-oxa-24α,26α,27α-trihomo-1α,25-(OH)₂-D₃), MC 1288, GS 1558, CB1093, 1,25-(OH)₂-16-ene-D₃, 1,25-(OH)₂-16-ene-23-yne-D₃, and25-(OH)₂-16-ene-23-yne-D₃, 22-oxacalcitriol; 1α-(OH)D₅ (University ofIllinois), ZK 161422 and ZK 157202 (Institute of MedicalChemistry-Schering AG), alfacalcidol, calcifediol, calcipotriol(calcipotriene), maxacalcitriol, colecalciferol, doxercalciferol,ergocalciferol, falecalcitriol, lexacalcitol, maxacalcitol,paricalcitol, secalciferol, seocalcitol, tacalcitol, calcipotriene,calcitriol, and other analogs as disclosed in U.S. Pat. No. 5,994,332),pyrogallol, and tacalcitol.

The compounds disclosed herein can also be administered with vitaminsand derivatives thereof including Vitamin A, ascorbic acid (Vitamin C),alpha-tocopherol (Vitamin E), 7-dehydrocholesterol (Vitamin D), VitaminK, alpha-lipoic acid, lipid soluble anti-oxidants, and the like. Theycan also be used with skin protectants, such allantoin and esculin.

In addition to TRPA1, other TRP channels have been implicated in painreception and/or sensation. For example, certain TRPM channels includingTRPM8 have been implicated in the reception and/or sensation of pain.Accordingly, in certain embodiments, the methods of the presentinvention include treating pain by administering (i) a combination of aselective TRPA1 antagonist and a selective TRPM8 antagonist; (ii) acombination of a selective TRPA1 antagonist, a selective TRPM8antagonist, and one or more of a selective TRPV1 and/or TRPV3antagonist; (iii) a cross-TRP inhibitor that antagonizes a function ofTRPA1 and TRPM8; or (iv) a pan inhibitor that antagonizes a function ofTRPA1, TRPM8, and one or more of TRPV1 and TRPV3.

In certain embodiments, a compound of the invention is conjointlyadministered with one or more additional compounds that antagonize thefunction of a different channel. By way of example, a compound of theinvention may be conjointly administered with one or more compounds thatantagonize TRPV1, TRPM8, and/or TRPV3. The compound(s) that antagonizeTRPV1, TPRM8, or TRPV3 may be selective for TRPV1, TRPM8 or TRPV3 (e.g.,inhibit TRPV1 or TRPV3 10, 100, or 1000 fold more strongly than TRPA1).Alternatively, the compound(s) that antagonize TRPV1 or TRPV3 may crossreact with other TRP channels.

Pharmaceutical Compositions

While it is possible for a compound disclosed herein to be administeredalone, it is preferable to administer the compound as a pharmaceuticalformulation, where the compound is combined with one or morepharmaceutically acceptable excipients or carriers. The compoundsdisclosed herein may be formulated for administration in any convenientway for use in human or veterinary medicine. In certain embodiments, thecompound included in the pharmaceutical preparation may be activeitself, or may be a prodrug, e.g., capable of being converted to anactive compound in a physiological setting.

The phrase “pharmaceutically acceptable” is employed herein to refer tothose compounds, materials, compositions, and/or dosage forms which are,within the scope of sound medical judgment, suitable for use in contactwith the tissues of human beings and animals without excessive toxicity,irritation, allergic response, or other problem or complication,commensurate with a reasonable benefit/risk ratio.

Examples of pharmaceutically acceptable carriers include: (1) sugars,such as lactose, glucose and sucrose; (2) starches, such as corn starchand potato starch; (3) cellulose, and its derivatives, such as sodiumcarboxymethyl cellulose, ethyl cellulose and cellulose acetate; (4)powdered tragacanth; (5) malt; (6) gelatin; (7) talc; (8) excipients,such as cocoa butter and suppository waxes; (9) oils, such as peanutoil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil andsoybean oil; (10) glycols, such as propylene glycol; (11) polyols, suchas glycerin, sorbitol, mannitol and polyethylene glycol; (12) esters,such as ethyl oleate and ethyl laurate; (13) agar; (14) bufferingagents, such as magnesium hydroxide and aluminum hydroxide; (15) alginicacid; (16) pyrogen-free water; (17) isotonic saline; (18) Ringer'ssolution; (19) ethyl alcohol; (20) phosphate buffer solutions; (21)cyclodextrins such as anionically charged sulfobutyl etherβ-cyclodextrins or hydroxypropyl-beta-cyclodextrins; and (22) othernon-toxic compatible substances employed in pharmaceutical formulations.

Examples of pharmaceutically acceptable antioxidants include: (1) watersoluble antioxidants, such as ascorbic acid, cysteine hydrochloride,sodium bisulfate, sodium metabisulfite, sodium sulfite and the like; (2)oil-soluble antioxidants, such as ascorbyl palmitate, butylatedhydroxyanisole (BHA), butylated hydroxytoluene (BHT), lecithin, propylgallate, alpha-tocopherol, and the like; and (3) metal chelating agents,such as citric acid, ethylenediamine tetraacetic acid (EDTA), sorbitol,tartaric acid, phosphoric acid, and the like.

Solid dosage forms (e.g., capsules, tablets, pills, dragees, powders,granules and the like) can include one or more pharmaceuticallyacceptable carriers, such as sodium citrate or dicalcium phosphate,and/or any of the following: (1) fillers or extenders, such as starches,lactose, sucrose, glucose, mannitol, and/or silicic acid; (2) binders,such as, for example, carboxymethylcellulose, alginates, gelatin,polyvinyl pyrrolidone, sucrose and/or acacia; (3) humectants, such asglycerol; (4) disintegrating agents, such as agar-agar, calciumcarbonate, potato or tapioca starch, alginic acid, certain silicates,and sodium carbonate; (5) solution retarding agents, such as paraffin;(6) absorption accelerators, such as quaternary ammonium compounds; (7)wetting agents, such as, for example, cetyl alcohol and glycerolmonostearate; (8) absorbents, such as kaolin and bentonite clay; (9)lubricants, such a talc, calcium stearate, magnesium stearate, solidpolyethylene glycols, sodium lauryl sulfate, and mixtures thereof; and(10) coloring agents.

Liquid dosage forms can include pharmaceutically acceptable emulsions,microemulsions, solutions, suspensions, syrups and elixirs. In additionto the active ingredient, the liquid dosage forms may contain inertdiluents commonly used in the art, such as, for example, water or othersolvents, solubilizing agents and emulsifiers, such as ethyl alcohol,isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol,benzyl benzoate, propylene glycol, 1,3-butylene glycol, oils (inparticular, cottonseed, groundnut, corn, germ, olive, castor and sesameoils), glycerol, tetrahydrofuryl alcohol, polyethylene glycols and fattyacid esters of sorbitan, and mixtures thereof.

Suspensions, in addition to the active compounds, may contain suspendingagents as, for example, ethoxylated isostearyl alcohols, polyoxyethylenesorbitol and sorbitan esters, microcrystalline cellulose, aluminummetahydroxide, bentonite, agar-agar and tragacanth, and mixturesthereof.

Ointments, pastes, creams and gels may contain, in addition to an activecompound, excipients, such as animal and vegetable fats, oils, waxes,paraffins, starch, tragacanth, cellulose derivatives, polyethyleneglycols, silicones, bentonites, silicic acid, talc and zinc oxide, ormixtures thereof.

Powders and sprays can contain, in addition to an active compound,excipients such as lactose, talc, silicic acid, aluminum hydroxide,calcium silicates and polyamide powder, or mixtures of these substances.Sprays can additionally contain customary propellants, such aschlorofluorohydrocarbons and volatile unsubstituted hydrocarbons, suchas butane and propane.

The formulations may conveniently be presented in unit dosage form andmay be prepared by any methods well known in the art of pharmacy. Theamount of active ingredient which can be combined with a carriermaterial to produce a single dosage form will vary depending upon thehost being treated, the particular mode of administration. The amount ofactive ingredient that can be combined with a carrier material toproduce a single dosage form will generally be that amount of thecompound which produces a therapeutic effect. Generally, out of onehundred percent, this amount will range from about 1 percent to aboutninety-nine percent of active ingredient, preferably from about 5percent to about 70 percent, most preferably from about 10 percent toabout 30 percent.

The tablets, and other solid dosage forms of the pharmaceuticalcompositions disclosed herein, such as dragees, capsules, pills andgranules, may optionally be scored or prepared with coatings and shells,such as enteric coatings and other coatings well known in thepharmaceutical-formulating art. They may also be formulated so as toprovide slow or controlled release of the active ingredient thereinusing, for example, hydroxypropylmethyl cellulose in varying proportionsto provide the desired release profile, other polymer matrices,liposomes and/or microspheres. They may be sterilized by, for example,filtration through a bacteria-retaining filter, or by incorporatingsterilizing agents in the form of sterile solid compositions that can bedissolved in sterile water, or some other sterile injectable mediumimmediately before use. These compositions may also optionally containopacifying agents and may be of a composition that they release theactive ingredient(s) only, or preferentially, in a certain portion ofthe gastrointestinal tract, optionally, in a delayed manner. Examples ofembedding compositions that can be used include polymeric substances andwaxes. The active ingredient can also be in micro-encapsulated form, ifappropriate, with one or more of the above-described excipients.

Dosage forms for the topical or transdermal administration of a compoundof this invention include powders, sprays, ointments, pastes, creams,lotions, gels, solutions, patches and inhalants. The active compound maybe mixed under sterile conditions with a pharmaceutically acceptablecarrier, and with any preservatives, buffers, or propellants that may berequired.

The formulations disclosed herein can be delivered via a device.Exemplary devices include, but are not limited to, a catheter, wire,stent, or other intraluminal device. Further exemplary delivery devicesalso include a patch, bandage, mouthguard, or dental apparatus.Transdermal patches have the added advantage of providing controlleddelivery of a compound disclosed herein to the body. Such dosage formscan be made by dissolving or dispersing the compound in the propermedium. Absorption enhancers can also be used to increase the flux ofthe compound across the skin. The rate of such flux can be controlled byeither providing a rate controlling membrane or dispersing the compoundin a polymer matrix or gel.

Ophthalmic formulations, eye ointments, drops, solutions and the like,are also contemplated as being within the scope of this invention.

In some cases, in order to prolong the effect of a drug, it is desirableto slow the absorption of the drug from subcutaneous or intramuscularinjection. This may be accomplished by the use of a liquid suspension ofcrystalline or amorphous material having poor water solubility. The rateof absorption of the drug then depends upon its rate of dissolution,which, in turn, may depend upon crystal size and crystalline form.Alternatively, delayed absorption of a parenterally administered drugform is accomplished by dissolving or suspending the drug in an oilvehicle.

Injectable depot forms are made by forming microencapsule matrices ofthe subject compounds in biodegradable polymers such aspolylactide-polyglycolide. Depending on the ratio of drug to polymer,and the nature of the particular polymer employed, the rate of drugrelease can be controlled. Examples of other biodegradable polymersinclude poly(orthoesters) and poly(anhydrides). Depot injectableformulations are also prepared by entrapping the drug in liposomes ormicroemulsions that are compatible with body tissue.

When the compounds disclosed herein are administered as pharmaceuticals,to humans and animals, they can be given per se or as a pharmaceuticalcomposition containing, for example, 0.1 to 99.5% (more preferably, 0.5to 90%) of active ingredient in combination with a pharmaceuticallyacceptable carrier.

The formulations can be administered topically, orally, transdermally,rectally, vaginally, parentally, intranasally, intrapulmonary,intraocularly, intravenously, intramuscularly, intraarterially,intrathecally, intracapsularly, intraorbitally, intracardiacly,intradermally, intraperitoneally, transtracheally, subcutaneously,subcuticularly, intraarticularly, subcapsularly, subarachnoidly,intraspinally, intrasternally or by inhalation.

One specific embodiment is an antitussive composition for peroraladministration comprising an agent that inhibits both a TRPA1-mediatedcurrent with an IC₅₀ of 1 micromolar or less, and an orally-acceptablepharmaceutical carrier in the form of an aqueous-based liquid, or soliddissolvable in the mouth, selected from the group consisting of syrup,elixer, suspension, spray, lozenge, chewable lozenge, powder, andchewable tablet. Such antitussive compositions can include one or moreadditional agents for treating cough, allergy or asthma symptom selectedfrom the group consisting of: antihistamines, 5-lipoxygenase inhibitors,leukotriene inhibitors, H3 inhibitors, β-adrenergic receptor agonists,xanthine derivatives, α-adrenergic receptor agonists, mast cellstabilizers, expectorants, NK1, NK2 and NK3 tachykinin receptorantagonists, and GABA_(B) agonists.

Still another embodiment is a metered dose aerosol dispenser containingan aerosol pharmaceutical composition for pulmonary or nasal deliverycomprising an agent that inhibits a TRPA1-mediated current with an IC₅₀of 1 micromolar or less. For instance, it can be a metered dose inhaler,a dry powder inhaler or an air-jet nebulizer.

Dosages

Actual dosage levels of the active ingredients in the pharmaceuticalcompositions of this invention may be varied so as to obtain an amountof the active ingredient that is effective to achieve the desiredtherapeutic response for a particular patient, composition, and mode ofadministration, without being toxic to the patient.

The selected dosage level will depend upon a variety of factorsincluding the activity of the particular compound disclosed hereinemployed, or the ester, salt or amide thereof, the route ofadministration, the time of administration, the rate of excretion of theparticular compound being employed, the duration of the treatment, otherdrugs, compounds and/or materials used in combination with theparticular compound employed, the age, sex, weight, condition, generalhealth and prior medical history of the patient being treated, and likefactors well known in the medical arts.

A physician or veterinarian having ordinary skill in the art can readilydetermine and prescribe the effective amount of the pharmaceuticalcomposition required. For example, the physician or veterinarian couldstart doses of the compounds of the invention employed in thepharmaceutical composition at levels lower than that required in orderto achieve the desired therapeutic effect and gradually increase thedosage until the desired effect is achieved.

In general, a suitable daily dose of a compound of the invention will bethat amount of the compound that is the lowest dose effective to producea therapeutic effect. Such an effective dose will generally depend uponthe factors described above. Generally, intravenous,intracerebroventricular and subcutaneous doses of the compounds of thisinvention for a patient will range from about 0.0001 to about 100 mg perkilogram of body weight per day. For example, the dose can be 1-50,1-25, or 5-10 mg/kg.

If desired, the effective daily dose of the active compound may beadministered as two, three, four, five, six or more sub-dosesadministered separately at appropriate intervals throughout the day,optionally, in unit dosage forms.

Disease and Injury Models

Compounds that antagonize TRPA1 function may be useful in theprophylaxis and treatment of any of the foregoing injuries, diseases,disorders, or conditions. In addition to in vitro assays of the activityof these compounds, their efficacy can be readily tested in one or moreanimal models. There are numerous animal models for studying pain. Thevarious models use various agents or procedures to simulate painresulting from injuries, diseases, or other conditions. Blackburn-Munro(2004) Trends in Pharmacological Sciences 25: 299-305 (see, for example,Tables 1, 3, or 4). Behavioral characteristics of challenged animals canthen be observed. Compounds or procedures that may reduce pain in theanimals can be readily tested by observing behavioral characteristics ofchallenged animals in the presence versus the absence of the testcompound(s) or procedure.

Exemplary behavioral tests used to study chronic pain include tests ofspontaneous pain, allodynia, and hyperalgesia. Id. To assess spontaneouspain, posture, gait, nocifensive signs (e.g., paw licking, excessivegrooming, excessive exploratory behavior, guarding of the injured bodypart, and self-mutilation) can be observed. To measure evoked pain,behavioral responses can be examined following exposure to heat (e.g.,thermal injury model).

Exemplary animal models of pain include, but are not limited to, theChung model, the carageenan induced hyperalgesia model, the Freund'scomplete adjuvant induced hyperalgesia model, the thermal injury model,the formalin model and the Bennett Model. The Chung model of neuropathicpain (without inflammation) involves ligating one or more spinal nerves.Chung et al. (2004) Methods Mol Med 99: 35-45; Kim and Chung (1992) Pain50: 355-363. Ligation of the spinal nerves results in a variety ofbehavioral changes in the animals including heat hyperalgesia, coldallodynia, and ongoing pain. Compounds that antagonize TRPA1 can beadministered to ligated animals to assess whether they diminish theseligation-induced behavioral changes in comparison to that observed inthe absence of compound.

Carageenan induced hyperalgesia and Freund's complete adjuvant (FCA)induced hyperalgesia are models of inflammatory pain. Walker et al.(2003) Journal of Pharmacol Exp Ther 304: 56-62; McGaraughty et al.(2003) Br J Pharmacol 140: 1381-1388; Honore et al. (2005) J PharmacolExp Ther. Compounds that antagonize TRPA1 can be administered tocarrageenan or FCA challenged animals to assess whether they diminishthermal hyperalgesia in comparison to that observed in the absence ofcompound. In addition, the ability of compounds that antagonize TRPA1function to diminish cold and/or mechanical hypersensitivity can also beassessed in these models. Typically, the carrageenan inducedhyperalgesia model is believed to mimic acute inflammatory pain and theCFA model is believed to mimic chronic pain and chronic inflammatorypain.

Exemplary models of inflammatory pain include the rat model ofintraplantar bradykinin injection. Briefly, the baseline thermalsensitivity of the animals is assessed on a Hargreave's apparatus. TRPA1blockers are then administered systemically. Bradykinin is subsequentlyinjected into the paw and a hyperalgesia is allowed to develop. Thermalescape latency is then measured at multiple time points over the nextfew hours (Chuang et al., 2001; Vale et al., 2004).

Inflammation is often an important contributing factor to pain. As such,it is useful to identify compounds that act as anti-inflammatories. Manycompounds that reduce neural activity also prevent neurogenicinflammation. To measure inflammation directly, the volume of a rat pawcan be assessed using a plethysmometer. After baseline measurement istaken, carrageenan can be injected into the paw and the volume can bemonitored over the course of hours in animals that have been treatedwith vehicle or drug. Drugs that reduce the paw swelling are consideredto be anti-inflammatory.

Migraines are associated with significant pain and inability to completenormal tasks. Several models of migraine exist including the ratneurogenic inflammation model, (see Buzzi et al (1990) Br J Pharmacol;99:202-206), and the Burstein Model (see Strassman et al., (1996) Nature384: 560-564).

The Bennett model uses prolonged ischemia of the paw to mirror chronicpain. Xanthos et al. (2004) J Pain 5: S1. This provides an animal modelfor chronic pain including post-operative pain, complex regional painsyndrome, and reflex sympathetic dystrophy. Prolonged ischemia inducesbehavioral changes in the animals including hyperalgesia to mechanicalstimuli, sensitivity to cold, pain behaviors (e.g., paw shaking,licking, and/or favoring), and hyperpathia. Compounds that antagonizeTRPA1 can be administered to challenged animals to assess whether theydiminish any or all of these behaviors in comparison to that observed inthe absence of compound. Similar experiments can be conducted in athermal injury or UV-burn model which can be used to mimicpost-operative pain.

Additional models of neuropathic pain include central pain models basedon spinal cord injury. Chronic pain is generated by inducing a spinalcord injury, for example, by dropping a weight on a surgically exposedarea of spinal cord (e.g., weight-drop model). Spinal cord injury canadditionally be induced by crushing or compressing the spinal cord, bydelivering neurotoxin, using photochemicals, or by hemisecting thespinal cord. Wang and Wang (2003).

Additional models of neuropathic pain include peripheral nerve injurymodels. Exemplary models include, but are not limited to, the neuromamodel, the Bennett model, the Seltzer model, the Chung model (ligationat either L5 or L5/L6), the sciatic cryoneurolysis model, the inferiorcaudal trunk resection model, and the sciatic inflammatory neuritismodel. Id.

Exemplary models of neuropathic pain associated with particular diseasesare also available. Diabetes and shingles are two diseases oftenaccompanied by neuropathic pain. Even following an acute shinglesepisodes, some patients continue to suffer from postherpetic neuralgiaand experience persistent pain lasting years. Neuropathic pain caused byshingles and/or postherpetic neuralgia can be studied in thepostherpetic neuralgia model (PHN). Diabetic neuropathy can be studiedin diabetic mouse models, as well as chemically induced models ofdiabetic neuropathy. Wang and Wang (2003).

As outlined above, cancer pain may have any of a number of causes, andnumerous animal models exist to examine cancer pain related to, forexample, chemotherapeutics or tumor infiltration. Exemplary models oftoxin-related cancer pain include the vincristine-induced peripheralneuropathy model, the taxol-induced peripheral neuropathy model, and thecisplatin-induced peripheral neuropathy model. Wang and Wang (2003). Anexemplary model of cancer pain caused by tumor infiltration is thecancer invasion pain model (CIP). Id.

Primary and metastatic bone cancers are associated with tremendous pain.Several models of bone cancer pain exist including the mouse femur bonecancer pain model (FBC), the mouse calcaneus bone cancer pain model(CBC), and the rat tibia bone cancer model (TBC). Id.

An additional model of pain is the formalin model. Like the carrageenanand CFA models, the formalin model involves injection of an irritantintradermally or intraperitoneally into an animal. Injection offormalin, a 37 percent solution of formaldehyde, is the most commonlyused agent for intradermal paw injection (the formalin test). Injectionof a 0.5 to 15 percent solution of formalin (usually about 3.5%) intothe dorsal or plantar surface of the fore- or hindpaw produces abiphasic painful response of increasing and decreasing intensity forabout 60 minutes after the injection. Typical responses include the pawbeing lifted, licked, nibbled, or shaken. These responses are considerednociceptive. The initial phase of the response (also known as the EarlyPhase), which lasts 3 to 5 minutes, is probably due to direct chemicalstimulation of nociceptors. This is followed by 10 to 15 minutes duringwhich animals display little behavior suggestive of nociception. Thesecond phase of this response (also known as the Late Phase) startsabout 15 to 20 minutes after the formalin injection and lasts 20 to 40minutes, initially rising with both number and frequency of nociceptivebehaviors, reaching a peak, then falling off. The intensities of thesenociceptive behaviors are dependent on the concentration of formalinused. The second phase involves a period of sensitization during whichinflammatory phenomena occur. The two phases of responsiveness toformalin injection makes the formalin model an appropriate model forstudying mociceptive and acute inflammatory pain. It may also model, insome respects, neuropathic pain.

In addition to any of the foregoing models of chronic pain, compoundsthat antagonize TRPA1 function can be tested in one or more models ofacute pain. Valenzano et al. (2005) Neuropharmacology 48: 658-672.Regardless of whether compounds are tested in models of chronic pain,acute pain, or both, these studies are typically (though notexclusively) conducted, for example, in mice, rats, or guinea pigs.Additionally, compounds can be tested in various cell lines that providein vitro assays of pain. Wang and Wang (2003).

Many individuals seeking treatment for pain suffer from visceral pain.Animal models of visceral pain include the rat model of inflammatoryuterine pain (Wesselmann et al., (1997) Pain 73:309-317), injection ofmustard oil into the gastrointestinal tract to mimic irritable bowelsyndrome (Kimball et al., (2005) Am J Physiol Gastrointest LiverPhysiol, 288(6):G1266-73), injection of mustard oil into the bladder tomimic overactive bladder or bladder cystitis (Riazimand (2004), BJU 94:158-163). The effectiveness of a TRPA1 compound can be assessed by adecrease in writhing, gastrointestinal inflammation or bladderexcitability.

For testing the efficacy of TRPA1 antagonists for the treatment ofcough, experiments using the conscious guinea pig model of cough can bereadily conducted. Tanaka and Maruyama (2003) Journal Pharmacol Sci 93:465-470; McLeod et al. (2001) Br J Pharmacol 132: 1175-1178. Briefly,guinea pigs serve as a useful animal model for cough because, unlikeother rodents such as mice and rats, guinea pigs actually cough.Furthermore, guinea pig coughing appears to mimic human coughing interms of the posture, behavior, and appearance of the coughing animal.

To induce cough, conscious guinea pigs are exposed to an inducing agentsuch as citric acid or capsaicin. The response of the animal is measuredby counting the number of coughs. The effectiveness of a coughsuppressing agent, for example a compound that inhibits TRPA1, can bemeasured by administering the agent and assessing the ability of theagent to decrease the number of coughs elicited by exposure to citricacid, capsaicin, or other similar cough-inducing agent. In this way,TRPA1 inhibitors for use in the treatment of cough can be readilyevaluated and identified.

Additional models of cough include the unconscious guinea pig model.Rouget et al. (2004) Br J Pharmacol 141: 1077-1083. Either of theforegoing models can be adapted for use with other animals capable ofcoughing. Exemplary additional animals capable of coughing include catsand dogs.

Numerous rodent models of incontinence exist. These include models ofincontinence induced by nerve damage, urethral impingement andinflammation. Models of urethral impingement include the rat bladderoutflow obstruction model. (Pandita, R K, and Andersson K E. Effects ofintravesical administration of the K⁺ channel opener, Z.D6169, inconscious rats with and without bladder outflow obstruction. J Urol 162:943-948, 1999). Inflammatory models include injection of mustard oilinto the bladder.

To test the effectiveness of a TRPA1 inhibitor compound in treatingincontinence, varying concentrations of compound (e.g., low, medium, andhigh concentration) can be administered to rats following surgicalpartial bladder outlet obstruction (BOO). Efficacy of the varying dosesof TRPA1 inhibitory compound can be compared to controls administeredexcipients alone (sham control). Efficacy can further be compared torats administered a positive control, such as atropine. Atropine isexpected to decrease bladder over-activity following partial bladderoutlet obstruction in the BOO model. Note that when testing compounds inthe BOO model, compounds can be administered directly to the bladder orurethra (e.g., by catheter) or compounds can be administeredsystemically (e.g., orally, intraveneously, intraperitoneally, etc).

Several rat models of pancreatitic pain have recently been described(Lu, 2003, Anesthesiology 98(3): 734-740; Winston et al., 2003, Journalof Pain 4(6): 329-337). Lu et al. induced pancreatitis by systemicdelivery of dibutylin dichloride in rats. Rats showed an increase inwithdrawal events after von Frey filament stimulation of the abdomen anddecreased withdrawal latency after thermal stimulation during a periodof 7 days. The pain state induced in these animals was alsocharacterized by increased levels of substance P in spinal cords (Lu, etal., 2003). To test the efficacy of a TRPA1 inhibitor in this model, aTRPA1 inhibitor can be administered following or concurrently withdelivery of dibutylin dichloride. Control animals can be administered acarrier or a known pain reliever. Indicia of pain can be measured.Efficacy of a TRPA1 inhibitor can be evaluated by comparing the indiciaof pain observed in animals receiving a TRPA1 inhibitor to that ofanimals that did not receive a TRPA1 inhibitor. Additionally, efficacyof a TRPA1 inhibitor can be compared to that of known pain medicaments.

The efficacy of von Frey filament testing as a means to measurenociceptive behavior was also shown by inducing pancreatitis by systemicL-arginine administration (Winston et al, 2003). The efficacy of a TRPA1inhibitor can similarly be tested following pancreatitis induced bysystemic L-arginine administration.

Lu et al. also described direct behavioral assays for pancreatic painusing acute noxious stimulation of the pancreas via an indwelling ductalcanula in awake and freely moving rats. These assays included cagecrossing, rearing, and hind limb extension in response tointrapancreatic bradykinin infusion. Intrathecal administration ofeither D-APV (NMDA receptor antagonist) or morphine alone partiallyreduced visceral pain behaviors in this model. Combinations of bothreduced pain behaviors to baseline. The efficacy of a TRPA1 inhibitorcan similarly be tested in this system.

Any of the foregoing animal models may be used to evaluate the efficacyof a TRPA1 inhibitor in treating pain associated with pancreatitis. Theefficacy can be compared to a no teatment or placebo control.Additionally or alternatively, efficacy can be evaluated in comparisonto one or more known pain relieving medicaments.

The following examples are meant to be illustrative and are not meant tobe limiting in any way.

EXAMPLES Example 1 Synthesis of Exemplary Compounds

The compounds disclosed herein can be prepared using the scheme outlinedbelow.

Example 2 Synthesis of Additional Exemplary Compounds

Ethyl3-ethyl-5,7-dioxo-6,7-dihydro-5H-cyclopenta[b]pyridine-6-carboxylate(Compound A)

The mixture of 5-ethylpyridine-2,3-dicarboxylic acid (1.620 g, 8.3 mmol)in anhydrous Ac₂O (4.7 mL) was mixed and cooled to 0° C. To this mixtureat 0° C. was slowly added was slowly added ethyl 3-oxobutanoate (1.05mL, 8.3 mmol) and anhydrous Et₃N (2.3 mL, 16.6 mol) and then thereaction was allowed to stir at room temperature for 3 days. Thereaction was diluted with HCl aqueous solution (90 mL, 0.27 M). Theaqueous phase was washed with ethyl acetate twice. Golden needle crystalwas crystallized out from aqueous phase to give the target compound (949mg, 46%).

Compound B and C:

Ethyl3-ethyl-5,7-dioxo-6,7-dihydro-5H-cyclopenta[b]pyridine-6-carboxylate(600 mg, 2.4 mmol), 3-ethoxybenzaldehyde (364 mg, 2.4 mmol) and urea(288 mg, 4.8 mmol) was added to acetic acid (2.5 mL) and the reactionwas heated at 90° C. for 4 hours. The reaction was concentrated in highvacuo. The residue was purified by column chromatography (MeOH:DCM=1:100 to 1:25) to give the target compound B (20 mg) and compound C(14.4 mg) as yellow solids. The structures were determined by ¹H-¹³CHMBC NMR

Example 2 Patch Clamp Experiments

Patch clamp experiments permit the detection of currents through theTRPA1 channel in the cell line described above. The whole-cellconfiguration of the patch clamp technique was used to test thecompounds described herein. In normal whole-cell patch clamp recordings,a glass electrode is brought into contact with a single cell and ahigh-resistance (gigaohm) seal is established with the cell membrane.The membrane is then ruptured to achieve the whole-cell configuration,permitting control of the voltage of the cell membrane and measurementof currents flowing across the membrane using the amplifier attached tothe electrode and resulting in the replacement of cytoplasm with thepipette solution.

TRPA1 cells were induced 20-48 hours, removed from growth plates, andreplated at low density (to attain good single-cell physical separation)on glass coverslips for measurement. In some cases, cells were grown inlow density overnight on glass coverslips. Potential blockers weretested for ability to block current in the continued presence of AITC.

Example 3 Testing of TRPA1 Antagonists in a Thermal Injury Model of Pain

The thermal injury model can be used to evaluate the effectiveness of anexemplary TRPA1 inhibitor in the treatment of nociceptive pain using thefollowing protocol. Male Holtzman rats (approximately 300 grams) may betested on thermal escape using a Hargreaves type apparatus. Under lightanesthesia, a thermal injury (52° C. for 45 seconds) can be applied toone heel. The animals can be tested for thermal escape latency of theinjured and uninjured paw before and at 30, 60, 80, and 120 minutesafter injury. Drug (a TRPA1 inhibitor) or vehicle (0.5% methylcellulose)can be administered after the baseline measurement and approximately15-20 minutes prior to the thermal injury. In addition to the escapelatency measurement, behavioral observations can be made throughout theexperiment.

Example 4 Testing of TRPA1 Antagonists in the Chung Model of NeuropathicPain

Briefly, male Sprague Dawley rats (approximately 175 grams) can beprepared with ligation of the L4/5 nerve roots. After 5-8 days, theanimals can be tested for tactile allodynia using Von Frey hairs.Thresholds can be assessed with the “up-down” method. Drug or vehiclecan be administered and the animals can be tested periodically.

INCORPORATION BY REFERENCE

All publications and patents mentioned herein are hereby incorporated byreference in their entirety as if each individual publication or patentwas specifically and individually indicated to be incorporated byreference.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

We claim:
 1. A compound having Formula VIII, or a pharmaceutically acceptable salt thereof:

wherein each of R¹ and R² is, independently, H, optionally substituted C₁₋₆ alkyl, arylalkyl, heteroarylalkyl, alkoxyalkyl, COR¹⁰, CO₂R¹⁰, CH₂CO₂R¹⁰, or CONHR¹⁰, where R¹⁰ is H or optionally substituted C₁₋₆ alkyl; each R₃ is, independently, hydroxyl, optionally substituted C₁₋₆ alkoxy, optionally substituted C₁₋₆ alkenyloxy, alkyloxyalkoxy, cyano, acyl, amino, optionally substituted alkylamino, aminoalkyl, amido, acylamino, alkylurea, alkylcarbamoyl, carboxyl, optionally substituted alkylcarboxyl, thioyl, optionally substituted alkylthio, SO₃H, optionally substituted alkylsulfinyl, or optionally substituted alkylsulfonyl; and n is 1-3.
 2. The compound of claim 1, wherein n is
 1. 3. The compound of claim 1, wherein R³ is alkoxy.
 4. The compound of claim 1, wherein R³ is alkenyloxy.
 5. The compound of claim 1, wherein each of R¹ and R² is, independently, H or optionally substituted C₁₋₆ alkyl.
 6. The compound of claim 1, wherein the compound has the Formula IX.


7. The compound of claim 1, wherein the compound has the Formula IXa.


8. A pharmaceutical composition comprising a pharmaceutically-acceptable carrier and a compound having Formula VIII, or a pharmaceutically acceptable salt thereof:

wherein each of R¹ and R² is, independently, H, optionally substituted C₁₋₆ alkyl, arylalkyl, heteroarylalkyl, alkoxyalkyl, COR¹⁰, CO₂R¹⁰, CH₂CO₂R¹⁰, or CONHR¹⁰, where R¹⁰ is H or optionally substituted C₁₋₆ alkyl; each R³ is, independently, hydroxyl, optionally substituted C₁₋₆ alkoxy, optionally substituted C₁₋₆ alkenyloxy, alkyloxyalkoxy, cyano, acyl, amino, optionally substituted alkylamino, aminoalkyl, amido, acylamino, alkylurea, alkylcarbamoyl, carboxyl, optionally substituted alkylcarboxyl, thioyl, optionally substituted alkylthio, SO₃H, optionally substituted alkylsulfinyl, or optionally substituted alkylsulfonyl; and n is 1-3.
 9. The composition of claim 8, wherein n is
 1. 10. The composition of claim 8, wherein R³ is alkoxy.
 11. The composition of claim 8, wherein R³ is alkenyloxy. 